Apptitude test-2

1) Circle : Circumference : : Square : ?
A.    Volume
B.    Area
C.    Diagonal
D.    Perimeter

2) Receptionist : Office : Hostess : ?
A.    Aircraft
B.    Crew
C.    Hospital
D.    Airport

3) Antonym of accord
A.    Act
B.    Dissent
C.    Policy
D.    Concord

4) Antonym of elevation
A.    Depreciation
B.    Depreciation
C.    Deflation
D.    Depression
           
5) Synonym of Mayhem
A.    Defeat
B.    Excitement
C.    Havoc
D.    Jubilation

6) Synonym of Revoke
A.    Repudiate
B.    Repeal
C.    Annul
D.    Force

7) grass: soil : : seaweed : ___________
A.    water
B.    river
C.    salty
D.    fish

8) Crumb : Bread ::
A.    Ounce : Unit
B.    Splinter : Wood
C.    Water : Bucket
D.    twine : rope

9) A told B that C is his father's nephew. D is A's cousin but not the brother of C. What relationship is there between D and C ?
A.    Father
B.    Sisters
C.    Aunt
D.    Mother

10) In a family, there are six members A, B, C, D, E and F. A and B are a married couple, A being the male member. D is the only son of C, who is the brother of A. E is the sister of D. B is the daughter-in-law of F, whose huasband has died. How is E related to C ?
A.    Nephew
B.    Daughter
C.    Sister
D.    Son-in-Law

11) If cushion is called pillow, pillow is called mat, mat is called bedsheet and bedsheet is called cover, which will be spread on the floor ?
A.    Cover
B.    Bedsheet
C.    Mat
D.    Pillow

12) If clock is called television, television is called radio, radio is called oven, oven is called grinder and grinder is called iron, in what will a lady bake ?
A.    Radio
B.    Oven
C.    Grinder
D.    Iron

In the following passage there are blanks, each of which has been numbered. These numbers are printed below the passage and against each, five words are suggested, one of which fits the blank appropriately. Find out the appropriate word in each case.

One day an expert in time management was …(13)… to a group of business management students and to drive home a point he used an …(14)… they will never forget. As he stood in front of a group of brilliant students he said, "Okay it’s …(15)… for a quiz." He then pulled out a one gallon jar and set it on the table in front of him.

13)
A.    expressing
B.    discussing
C.    speaking
D.    conveying
E.    addressing

14)
A.    illustration
B.    emblem
C.    expression
D.    impression
E.    imagination

15)
A.    scheduled
B.    time
C.    opportunity
D.    usual
E.    ready

16) 6, 11, 21, 36, 56, ?
A.    51
B.    71
C.    81
D.    41

17) 13, 35, 57, 79, 911, ?
A.    1145
B.    1113
C.    1117
D.    1110

18) If a person walks at 14 km/hr instead of 10 km/hr, he would have walked 20 km more. The actual distance travelled by him is
A.    50 km
B.    56 km
C.    70 km
D.    80 km

19) The ratio between the speeds of two trains is 7 : 8. If the second train runs 400 kms in 4 hours, then the speed of the first train is:
A.    70 km/hr
B.    75 km/hr
C.    84 km/hr
D.    87.5 km/hr

20) A square garden has fourteen posts along each side at equal interval. Find how many posts are there in all four sides.
A.    56
B.    44
C.    52
D.    60

21) Find the ratio of purchase price and sell price if there is loss of 12 1/2 %.
A.    7 : 8
B.    8 : 7
C.    2 : 25
D.    25 : 2

22) The sum of the present age of the father and his daughter is 42 years. 7 years later, the father will be 3 times old than the daughter. The present age of the father is
A.    32
B.    28
C.    35
D.    33

23) A train traveling at 48 kmph completely crosses another train having half its length and traveling in opposite direction at 42 kmph, in 12 seconds. It also passes a railway platform in 45 seconds. The length of the platform is
A.    550m
B.    600m
C.    450m
D.    400m

24) A train overtakes two persons who are walking in the same direction in which the train is going, at the rate of 2 kmph and 4 kmph and passes them completely in 9 and 10 seconds respectively. The length of the train is
A.    60 m
B.    65 m
C.    50 m
D.    55 m

25) A train 270 m long is moving at a speed of 24 kmph. It will cross a man coming from the opposite direction at a speed of 3 kmph, in
A.    30 s
B.    32 s
C.    34 s
D.    36 s

26) 12 men can complete a work in 18 days. Six days after they started working, 4 more men joined them. How many days will all of them together complete the remaining work?
A.    10 days
B.    8 days
C.    11 days
D.    9 days

27) A can do a certain work in 25 days which B alone can do in 20 days. A stared the work and was joined by B after 10 days. The work was completed in
A.    18 2/3 days
B.    16 2/3 days
C.    14 1/3 days
D.    15 1/3 days

28) A can do 1/3 of the work in 5 days and B can do 2/5 of the work in 10 days. In how many days both A and B toether can do the work?
A.    9 3/8 days
B.    8 2/3 days
C.    8 3/5 days
D.    9 3/5 days

29) T, R, P, N, L, ?, ?
A.    J, G
B.    J, H
C.    K, H
D.    K, I

30) BD, GI, LN, QS, ?
A.    TV
B.    UW
C.    WX
D.    VX

Aptitude Test-1

Time: 20 minutes

1) AZ, GT, MN, ?, YB
A.    KF
B.    RX
C.    SH
D.    TS

2) Find the odd one out
A.    door: bang
B.    piano: play
C.    drum: beat
D.    rain: platter

3) If wall is called window, window is called door, door is called floor, floor is callled roof and roof is callled ventilator, what will a person stand on ?
A.    Window
B.    Wall
C.    Floor
D.    Roof

4) There are six persons A, B, C, D , E and F. C is the sister of F. B is the brother of E's husband. D is the father of A and grandfather of F. There are two fathers, three brothers and a mother in the group. Which of the following is a group of brothers ?
A.    ABD
B.    ABF
C.    BFC
D.    BDF

5) A, E, I, O, ?
A.    T
B.    P
C.    G
D.    U

6) 4, 6, 12, 14, 28, 30, ?
A.    32
B.    64
C.    62
D.    60

7) 11, 13, 17, 19, 23, 29, 31, 37, 41, ?
A.    43
B.    47
C.    51
D.    53

8) A man complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.
A.    220 km
B.    224 km
C.    230 km
D.    234 km

9) A train 360 m long is running at a speed of 45 km/hr. In what time will it pass a bridge 140 m long?
A.    40 s
B.    45 s
C.    50 s
D.    55 s

10) A, B and C are employed to do a piece of work for Rs.529. A and B together are supposed to do 19/23 of the work and B and C together 8/23 of the work. What amount should A be paid?
A.    Rs.355
B.    Rs.345
C.    Rs.375
D.    Rs.335

11) A takes 3 days and B 2 days. Both worked together and finished the work, and got Rs.150. What is the share of A ?
A.    Rs.90
B.    Rs.60
C.    Rs.80
D.    Rs.50

12) It takes one minute to fill 3/7 th of a vessel. What is the time taken in minutes to fill the whole of the vessel?
A.    4/3
B.    3/4
C.    7/3
D.    3/2

13) A coin is placed on a plain paper. How many coins of the same size can be placed around it so that each of the coins touches its adjacent ones ?
A.    4
B.    5
C.    6
D.    7

14) If the Republic Day of India in 1980 falls on Saturday, X was born on March 3, 1980 and Y is older to X by four days, then Y’s birthday fell on
A.    Thursday
B.    Friday
C.    Wednesday
D.    None of these

15) ba_ba_bac_acb_cbac
A.    aacb
B.    bbca
C.    ccba
D.    cbac

16) bca_b_aabc _a_caa
A.    acab
B.    bcbb
C.    cbab
D.    ccab

17) COMPETITION : CONTESTANT ::
A.    trial : witness
B.    journey : traveler
C.    royalty : monarch
D.    election : candidate

18) INVENTORY : GOODS ::
A.    agenda : meeting
B.    snapshot : image
C.    ballot : voters
D.    roll : members

19) Find the odd one out
A.    December
B.    February
C.    March
D.    July

20) Find the odd one out
A.    Arc
B.    Diagonal
C.    Radius
D.    Diameter

21) If LBAEHC is the code for BLEACH, then which of the following is coded NBOLZKMH?
A.    BNLOKZHM
B.    MANKYJLG
C.    LOBNHMKZ
D.    OBNKZLHM

22) If ELCSUM is the code for MUSCLE, which word has the code LATIPAC?
A.    CAPRICE
B.    CONFESS
C.    CONDUCE
D.    CAPITAL

23) truthfulness: court : : cleanliness : _________
A.    virtue
B.    bath
C.    restaurant
D.    pig

24) lion: animal : : flower : ___________
A.    plant
B.    roots
C.    grass
D.    rose

Directions (1-5):In each of the following questions , a part of sentence is given in bold. Below each sentence, four choices numbered (A), (B), (C) and (D) are given which can substitute the part of the sentence in bold. Find out the choice which can correctly substitute that part of the sentence. The number of that choice is the answer. If 'No correction needed' is your answer, the choice is (E).

25) We must take it granted that he will not come for today's function.
A.    have it granted
B.    took it as granted
C.    taking it granted
D.    take it for granted
E.    No correction required

26) She unnecessarily picked up a quarrel with him and left the party.
A.    picking up
B.    picked
C.    picked on
D.    has picked up
E.    No correction required

27) He has the guts to rise from the occasion and come out successfully.
A.    in rising from
B.    to raise with
C.    to rise against
D.    to rise to
E.    No correction required

28) Antonym of "incidental"
A.    permissible
B.    usual
C.    conventional
D.    intentional

29) Synonym of "LAMENT"
A.    Console
B.    Condone
C.    Comment
D.    Complain

30) Synonym of "CANNY"
A.    Stout
B.    Clever
C.    Handsome
D.    Obstinate

Certifications for mobile app developers in India

Android Certified Application Developer

Advanced Training Consultants (ATC) for Android provides the training and certification for Android developers. The Android Certified Application Developer is the beginning-level certification for learning to design, build and maintain Android applications, and arguably the best certification you can have in your mobile app developer arsenal.
To earn the certification, candidates must pass the AND 401: Android Application Development Exam. The exam consists of 45 multiple choice questions (MCQ) to be completed within 90 minutes, with a clearing score of 70%. The exam content is based on the Android Application development course. Taking the course is not a prerequisite to sitting for the exam, and self-study guides are available to help prepare.
Upon successful completion of the exam candidates will receive their certificate and ID card online through e-mail within four weeks.

Oracle Java ME Mobile Application Developer

The prerequisites to appear for this exam can be rather expensive as one must first achieve certification as an Oracle Certified Professional (OCP), Java Programmer (SE5 or SE6) or a Sun certified programmer (SCJP), any edition.
Candidates are required to clear the Java (ME) Mobile Edition 1 Mobile Application Developer Certified Professional 1Z0-869 exam. In order to prepare for the exam you can take Java ME: Develop Applications for Mobile Phones training. In addition to this, you also need solid hands-on practice or on-the-job experience performing the tasks described in the exam topics.
The Oracle Java ME Mobile Application Developer exam consists of 68 MCQs to be completed within 158 minutes. Clearing the exam will require a minimum score of 58%.

MCSD Windows Store Apps

Microsoft Certified Solutions Developer (MCSD): Windows Store Apps certification confirms that you have the ability to develop fast and fluid Windows 8 apps. There are two paths to get this certification either using HTML5 or using C#. The prerequisite for this exam is that you should have one to two years of HTML5 or C# development experience as well as experience in Windows application development.
Microsoft recommends the HTML5 path for candidates with solid experience using JavaScript or web apps. .Net developers are encouraged to go the C# route. Regardless of the path, you will have to clear three exams. Note that Microsoft does not “identify exam formats or questions types” prior to the exam. There are however numerous, practice tests and study materials as well as videos of the sorts of exam questions offered. Check out Microsoft’s Virtual Academy for a more complete discussion on the exam, preparation and sitting for the exam.

Using HTML5
Exam 70-480: Programming in HTML5 with JavaScript and CSS3
Exam 70-481: Essentials of Developing Windows Store Apps Using HTML5 and JavaScript
Exam 70-482: Advanced Windows Store App Development Using HTML5 and JavaScript

Using C#
Exam 70-483: Programming in C#
Exam 70-484: Essentials of Developing Windows Store Apps Using C#
Exam 70-485: Advanced Windows Store App Development Using C#
This certification can be a bit pricey ($150 USD) per exam, but well worth your time and effort. If you are planning a career in mobile app development, this certification will give you a strong edge.

SAP Certified Development Associate – SMP Hybrid and Native Mobile Application Developer

For developers who support SAP/Sybase products, this is a solid intermediate-level certification. Credentialed individuals possess a foundational knowledge of Hybrid and Native mobile application development on the SAP Mobile Platform 2.3. This certification is offered and maintained by Enterprise Mobility, Germany.
Earning this certification will require that you have “several years of practical on-the-job experience.” The exam is made up of 80 MCQs, spread over nine topic areas, to be completed in three hours. A cut score of 65 percent is required.
Enterprise Mobility offers great support for candidates. If you subscribe to the SAB Learning Hub you will also receive access to relevant training materials and “Learning Rooms,” virtual learning spaces where SAP instructors are available to guide you through the required training.

IBM Certified Mobile Application Developer – Worklight V6.0

This is an intermediate level certification for developers with significant hands-on experience using Worklight V6.0 to develop mobile hybrid and native applications. Achieving this certification will enable you to develop client-side apps, server-side integration and security components as well as test, deploy and manage Worklight V6.0 apps.
To complete this certification candidates must pass Test C2180-278. The test consists of 54 questions with single or multiple answers. You will have 90 minutes to complete the exam, and a score of 66 percent to clear.
To prepare for this certification it is recommended that you be familiar with the job role description and the parameters this certification is based on. You should have knowledge of the topics outlined in the test objectives/skills measured on the test. To measure the current level of skills you can take a sample test as well.

Hadoop & MapReduce Interview Questions and Answers-1

1) What is Hadoop Map Reduce ?

For processing large data sets in parallel across a hadoop cluster, Hadoop MapReduce framework is used.  Data analysis uses a two-step map and reduce process.

2) How Hadoop MapReduce works?

In MapReduce, during the map phase it counts the words in each document, while in the reduce phase it aggregates the data as per the document spanning the entire collection. During the map phase the input data is divided into splits for analysis by map tasks running in parallel across Hadoop framework.

3) Explain what is shuffling in MapReduce ?

The process by which the system performs the sort and transfers the map outputs to the reducer as inputs is known as the shuffle

4) Explain what is distributed Cache in MapReduce Framework ?

Distributed Cache is an important feature provided by map reduce framework. When you want to share some files across all nodes in Hadoop Cluster, DistributedCache  is used.  The files could be an executable jar files or simple properties file.

5) Explain what is NameNode in Hadoop?

NameNode in Hadoop is the node, where Hadoop stores all the file location information in HDFS (Hadoop Distributed File System).  In other words, NameNode is the centrepiece of an HDFS file system.  It keeps the record of all the files in the file system, and tracks the file data across the cluster or multiple machines

7

6) Explain what is JobTracker in Hadoop? What are the actions followed by Hadoop?

In Hadoop for submitting and tracking MapReduce jobs,  JobTracker is used. Job tracker run on its own JVM process

Hadoop performs following actions in Hadoop

    Client application submit jobs to the job tracker
    JobTracker communicates to the Namemode to determine data location
    Near the data or with available slots JobTracker locates TaskTracker nodes
    On chosen TaskTracker Nodes, it submits the work
    When a task fails, Job tracker notify and decides what to do then.
    The TaskTracker nodes are monitored by JobTracker

7) Explain what is heartbeat in HDFS?

Heartbeat is referred to a signal used between a data node and Name node, and between task tracker and job tracker, if the Name node or job tracker does not respond to the signal, then it is considered there is some issues with data node or task tracker

8) Explain what combiners is and when you should use a combiner in a MapReduce Job?

To increase the efficiency of MapReduce Program, Combiners are used.  The amount of data can be reduced with the help of combiner’s that need to be transferred across to the reducers. If the operation performed is commutative and associative you can use your reducer code as a combiner.  The execution of combiner is not guaranteed in Hadoop

9) What happens when a datanode fails ?

When a datanode fails

    Jobtracker and namenode detect the failure
    On the failed node all tasks are re-scheduled
    Namenode replicates the users data to another node

10) Explain what is Speculative Execution?

In Hadoop during Speculative Execution a certain number of duplicate tasks are launched.  On different slave node, multiple copies of same map or reduce task can be executed using Speculative Execution. In simple words, if a particular drive is taking long time to complete a task, Hadoop will create a duplicate task on another disk.  Disk that finish the task first are retained and disks that do not finish first are killed.

11) Explain what are the basic parameters of a Mapper?

The basic parameters of a Mapper are

    LongWritable and Text
    Text and IntWritable

12) Explain what is the function of MapReducer partitioner?

The function of MapReducer partitioner is to make sure that all the value of a single key goes to the same reducer, eventually which helps evenly distribution of the map output over the reducers

13) Explain what is difference between an Input Split and HDFS Block?

Logical division of data is known as Split while physical division of data is known as HDFS Block

14) Explain what happens in textinformat ?

In textinputformat, each line in the text file is a record.  Value is the content of the line while Key is the byte offset of the line. For instance, Key: longWritable, Value: text

15) Mention what are the main configuration parameters that user need to specify to run Mapreduce Job ?

The user of Mapreduce framework needs to specify

    Job’s input locations in the distributed file system
    Job’s output location in the distributed file system
    Input format
    Output format
    Class containing the map function
    Class containing the reduce function
    JAR file containing the mapper, reducer and driver classes

16) Explain what is WebDAV in Hadoop?

To support editing and updating files WebDAV is a set of extensions to HTTP.  On most operating system WebDAV shares can be mounted as filesystems , so it is possible to access HDFS as a standard filesystem by exposing HDFS over WebDAV.

17)  Explain what is sqoop in Hadoop ?

To transfer the data between Relational database management (RDBMS) and Hadoop HDFS a tool is used known as Sqoop. Using Sqoop data can be transferred from RDMS like MySQL or Oracle into HDFS as well as exporting data from HDFS file to RDBMS

18) Explain how JobTracker schedules a task ?

The task tracker send out heartbeat messages to Jobtracker usually every few minutes to make sure that JobTracker is active and functioning.  The message also informs JobTracker about the number of available slots, so the JobTracker can stay upto date with where in the cluster work can be delegated

19) Explain what is Sequencefileinputformat?

Sequencefileinputformat is used for reading files in sequence. It is a specific compressed binary file format which is optimized for passing data between the output of one MapReduce job to the input of some other MapReduce job.

20) Explain what does the conf.setMapper Class do ?

Conf.setMapperclass  sets the mapper class and all the stuff related to map job such as reading data and generating a key-value pair out of the mapper

21) Explain what is Hadoop?

It is an open-source software framework for storing data and running applications on clusters of commodity hardware.  It provides enormous processing power and massive storage for any type of data.

22) Mention what is the difference between an RDBMS and Hadoop?
RDBMS    Hadoop
RDBMS is relational database management system    Hadoop is node based flat structure
It used for OLTP processing whereas Hadoop    It is currently used for analytical and for BIG DATA processing
In RDBMS, the database cluster uses the same data files stored in shared storage    In Hadoop, the storage data can be stored independently in each processing node.
You need to preprocess data before storing it    you don’t need to preprocess data before storing it

23) Mention Hadoop core components?

Hadoop core components include,

    HDFS
    MapReduce

24) What is NameNode in Hadoop?

NameNode in Hadoop is where Hadoop stores all the file location information in HDFS. It is the master node on which job tracker runs and consists of metadata.

25) Mention what are the data components used by Hadoop?

Data components used by Hadoop are

    Pig
    Hive

26) Mention what is the data storage component used by Hadoop?

The data storage component used by Hadoop is HBase.

27) Mention what are the most common input formats defined in Hadoop?

The most common input formats defined in Hadoop are;

    TextInputFormat
    KeyValueInputFormat
    SequenceFileInputFormat

28) In Hadoop what is InputSplit?

It splits input files into chunks and assign each split to a mapper for processing.

29) For a Hadoop job, how will you write a custom partitioner?

You write a custom partitioner for a Hadoop job, you follow the following path

    Create a new class that extends Partitioner Class
    Override method getPartition
    In the wrapper that runs the MapReduce
    Add the custom partitioner to the job by using method set Partitioner Class or – add the custom partitioner to the job as a config file

30) For a job in Hadoop, is it possible to change the number of mappers to be created?

No, it is not possible to change the number of mappers to be created. The number of mappers is determined by the number of input splits.

31) Explain what is a sequence file in Hadoop?

To store binary key/value pairs, sequence file is used. Unlike regular compressed file, sequence file support splitting even when the data inside the file is compressed.

32) When Namenode is down what happens to job tracker?

Namenode is the single point of failure in HDFS so when Namenode is down your cluster will set off.

33) Explain how indexing in HDFS is done?

Hadoop has a unique way of indexing. Once the data is stored as per the block size, the HDFS will keep on storing the last part of the data which say where the next part of the data will be.

34) Explain is it possible to search for files using wildcards?

Yes, it is possible to search for files using wildcards.

35) List out Hadoop’s three configuration files?

The three configuration files are

    core-site.xml
    mapred-site.xml
    hdfs-site.xml

36) Explain how can you check whether Namenode is working beside using the jps command?

Beside using the jps command, to check whether Namenode are working you can also use

/etc/init.d/hadoop-0.20-namenode status.

37) Explain what is “map” and what is “reducer” in Hadoop?

In Hadoop, a map is a phase in HDFS query solving.  A map reads data from an input location, and outputs a key value pair according to the input type.

In Hadoop, a reducer collects the output generated by the mapper, processes it, and creates a final output of its own.

38) In Hadoop, which file controls reporting in Hadoop?

In Hadoop, the hadoop-metrics.properties file controls reporting.

39) For using Hadoop list the network requirements?

For using Hadoop the list of network requirements are:

    Password-less SSH connection
    Secure Shell (SSH) for launching server processes

40) Mention what is rack awareness?

Rack awareness is the way in which the namenode determines on how to place blocks based on the rack definitions.

41) Explain what is a Task Tracker in Hadoop?

A Task Tracker in Hadoop is a slave node daemon in the cluster that accepts tasks from a JobTracker. It also sends out the heartbeat messages to the JobTracker, every few minutes, to confirm that the JobTracker is still alive.

42) Mention what daemons run on a master node and slave nodes?

    Daemons run on Master node is “NameNode”
    Daemons run on each Slave nodes are “Task Tracker” and “Data”

43) Explain how can you debug Hadoop code?

The popular methods for debugging Hadoop code are:

    By using web interface provided by Hadoop framework
    By using Counters

44) Explain what is storage and compute nodes?

    The storage node is the machine or computer where your file system resides to store the processing data
    The compute node is the computer or machine where your actual business logic will be executed.

45) Mention what is the use of Context Object?

The Context Object enables the mapper to interact with the rest of the Hadoop

system. It includes configuration data for the job, as well as interfaces which allow it to emit output.

46) Mention what is the next step after Mapper or MapTask?

The next step after Mapper or MapTask is that the output of the Mapper are sorted, and partitions will be created for the output.

47) Mention what is the number of default partitioner in Hadoop?

In Hadoop, the default partitioner is a “Hash” Partitioner.

48) Explain what is the purpose of RecordReader in Hadoop?

In Hadoop, the RecordReader loads the data from its source and converts it into (key, value) pairs suitable for reading by the Mapper.

49) Explain how is data partitioned before it is sent to the reducer if no custom partitioner is defined in Hadoop?

If no custom partitioner is defined in Hadoop, then a default partitioner computes a hash value for the key and assigns the partition based on the result.

50) Explain what happens when Hadoop spawned 50 tasks for a job and one of the task failed?

It will restart the task again on some other TaskTracker if the task fails more than the defined limit.

51) Mention what is the best way to copy files between HDFS clusters?

The best way to copy files between HDFS clusters is by using multiple nodes and the distcp command, so the workload is shared.

52) Mention what is the difference between HDFS and NAS?

HDFS data blocks are distributed across local drives of all machines in a cluster while NAS data is stored on dedicated hardware.

53) Mention how Hadoop is different from other data processing tools?

In Hadoop, you can increase or decrease the number of mappers without worrying about the volume of data to be processed.

54) Mention what job does the conf class do?

Job conf class separate different jobs running on the same cluster.  It does the job level settings such as declaring a job in a real environment.

55) Mention what is the Hadoop MapReduce APIs contract for a key and value class?

For a key and value class, there are two Hadoop MapReduce APIs contract

    The value must be defining the org.apache.hadoop.io.Writable interface
    The key must be defining the org.apache.hadoop.io.WritableComparable interface

56) Mention what are the three modes in which Hadoop can be run?

The three modes in which Hadoop can be run are

    Pseudo distributed mode
    Standalone (local) mode
    Fully distributed mode

57) Mention what does the text input format do?

The text input format will create a line object that is an hexadecimal number.  The value is considered as a whole line text while the key is considered as a line object. The mapper will receive the value as ‘text’ parameter while key as ‘longwriteable’ parameter.

58) Mention how many InputSplits is made by a Hadoop Framework?

Hadoop will make 5 splits

    1 split for 64K files
    2 split for 65mb files
    2 splits for 127mb files

59) Mention what is distributed cache in Hadoop?

Distributed cache in Hadoop is a facility provided by MapReduce framework.  At the time of execution of the job, it is used to cache file.  The Framework copies the necessary files to the slave node before the execution of any task at that node.

60) Explain how does Hadoop Classpath plays a vital role in stopping or starting in Hadoop daemons?

Classpath will consist of a list of directories containing jar files to stop or start daemons.

Big Data

Big data is defined as the voluminous amount of structured, unstructured or semi-structured data that has huge potential for mining but is so large that it cannot be processed using traditional database systems. Big data is characterized by its high velocity, volume and variety that requires cost effective and innovative methods for information processing to draw meaningful business insights. More than the volume of the data – it is the nature of the data that defines whether it is considered as Big Data or not.

What do the four V’s of Big Data denote?
IBM has a nice, simple explanation for the four critical features of big data:
a) Volume –Scale of data
b) Velocity –Analysis of streaming data
c) Variety – Different forms of data
d) Veracity –Uncertainty of data

How big data analysis helps businesses increase their revenue? Give example.
Big data analysis is helping businesses differentiate themselves – for example Walmart the world’s largest retailer in 2014 in terms of revenue - is using big data analytics to increase its sales through better predictive analytics, providing customized recommendations and launching new products based on customer preferences and needs. Walmart observed a significant 10% to 15% increase in online sales for $1 billion in incremental revenue. There are many more companies like Facebook, Twitter, LinkedIn, Pandora, JPMorgan Chase, Bank of America, etc. using big data analytics to boost their revenue.

Differentiate between Structured and Unstructured data.
Data which can be stored in traditional database systems in the form of rows and columns, for example the online purchase transactions can be referred to as Structured Data. Data which can be stored only partially in traditional database systems, for example, data in XML records can be referred to as semi structured data. Unorganized and raw data that cannot be categorized as semi structured or structured data is referred to as unstructured data. Facebook updates, Tweets on Twitter, Reviews, web logs, etc. are all examples of unstructured data.

Hadoop Interview Questions and Answers-1

1.What are real-time industry applications of Hadoop?
    Hadoop, well known as Apache Hadoop, is an open-source software platform for scalable and distributed computing of large volumes of data. It provides rapid, high performance and cost-effective analysis of structured and unstructured data generated on digital platforms and within the enterprise. It is used in almost all departments and sectors today.
    Some of the instances where Hadoop is used:
    • Managing traffic on streets
    • Streaming processing
    • Content Management and Archiving Emails
    • Processing Rat Brain Neuronal Signals using a Hadoop Computing Cluster
    • Fraud detection and Prevention
    • Advertisements Targeting Platforms are using Hadoop to capture and analyze click stream, transaction, video and social media data
    • Managing content, posts, images and videos on social media platforms
    • Analyzing customer data in real-time for improving business performance
    • Public sector fields such as intelligence, defense, cyber security and scientific research
    • Financial agencies are using Big Data Hadoop to reduce risk, analyze fraud patterns, identify rogue traders, more precisely target their marketing campaigns based on customer segmentation, and improve customer satisfaction
    • Getting access to unstructured data like output from medical devices, doctor’s notes, lab results, imaging reports, medical correspondence, clinical data, and financial data.

2.How is Hadoop different from other parallel computing systems?
Hadoop is a distributed file system, which lets you store and handle massive amount of data on a cloud of machines, handling data redundancy. Go through this HDFS content to know how the distributed file system works. The primary benefit is that since data is stored in several nodes, it is better to process it in distributed manner. Each node can process the data stored on it instead of spending time in moving it over the network.
On the contrary, in Relational database computing system, you can query data in real-time, but it is not efficient to store data in tables, records and columns when the data is huge.
Hadoop also provides a scheme to build a Column Database with Hadoop HBase, for runtime queries on rows.

3.What all modes Hadoop can be run in?
    Hadoop can run in three modes:
    1. Standalone Mode: Default mode of Hadoop, it uses local file stystem for input and output operations. This mode is mainly used for debugging purpose, and it does not support the use of HDFS. Further, in this mode, there is no custom configuration required for mapred-site.xml, core-site.xml, hdfs-site.xml files. Much faster when compared to other modes.
    2. Pseudo-Distributed Mode (Single Node Cluster): In this case, you need configuration for all the three files mentioned above. In this case, all daemons are running on one node and thus, both Master and Slave node are the same.
    3. Fully Distributed Mode (Multiple Cluster Node): This is the production phase of Hadoop (what Hadoop is known for) where data is used and distributed across several nodes on a Hadoop cluster. Separate nodes are allotted as Master and Slave.

4.Explain the major difference between HDFS block and InputSplit.
    In simple terms, block is the physical representation of data while split is the logical representation of data present in the block. Split acts a s an intermediary between block and mapper. Suppose we have two blocks:
    Block 1: ii nntteell
    Block 2: Ii ppaatt
    Now, considering the map, it will read first block from ii till ll, but does not know how to process the second block at the same time. Here comes Split into play, which will form a logical group of Block1 and Block 2 as a single block. It then forms key-value pair using inputformat and records reader and sends map for further processing With inputsplit, if you have limited resources, you can increase the split size to limit the number of maps. For instance, if there are 10 blocks of 640MB (64MB each) and there are limited resources, you can assign ‘split size’ as 128MB. This will form a logical group of 128MB, with only 5 maps executing at a time.
    However, if the ‘split size’ property is set to false, whole file will form one inputsplit and is processed by single map, consuming more time when the file is bigger.

5.What is distributed cache and what are its benefits?
    Distributed Cache, in Hadoop, is a service by MapReduce framework to cache files when needed.Once a file is cached for a specific job, hadoop will make it available on each data node both in system and in memory, where map and reduce tasks are executing.Later, you can easily access and read the cache file and populate any collection (like array, hashmap) in your code.
Benefits of using distributed cache are:
• It distributes simple, read only text/data files and/or complex types like jars, archives and others. These archives are then un-archived at the slave node.
• Distributed cache tracks the modification timestamps of cache files, which notifies that the files should not be modified until a job is executing currently.

6.Explain the difference between NameNode, Checkpoint NameNode and BackupNode.
    NameNode is the core of HDFS that manages the metadata – the information of what file maps to what block locations and what blocks are stored on what datanode. In simple terms, it’s the data about the data being stored. NameNode supports a directory tree-like structure consisting of all the files present in HDFS on a Hadoop cluster. It uses following files for namespace:
    fsimage file- It keeps track of the latest checkpoint of the namespace.
    edits file-It is a log of changes that have been made to the namespace since checkpoint.
    Checkpoint NameNode has the same directory structure as NameNode, and creates checkpoints for namespace at regular intervals by downloading the fsimage and edits file and margining them within the local directory. The new image after merging is then uploaded to NameNode.
    There is a similar node like Checkpoint, commonly known as Secondary Node, but it does not support the ‘upload to NameNode’ functionality.
    Backup Node provides similar functionality as Checkpoint, enforcing synchronization with NameNode. It maintains an up-to-date in-memory copy of file system namespace and doesn’t require getting hold of changes after regular intervals. The backup node needs to save the current state in-memory to an image file to create a new checkpoint.

7.What are the most common Input Formats in Hadoop?
    There are three most common input formats in Hadoop:
    • Text Input Format: Default input format in Hadoop.
    • Key Value Input Format: used for plain text files where the files are broken into lines
    • Sequence File Input Format: used for reading files in sequence
8.Define DataNode and how does NameNode tackle DataNode failures?
    DataNode stores data in HDFS; it is a node where actual data resides in the file system. Each datanode sends a heartbeat message to notify that it is alive. If the namenode does noit receive a message from datanode for 10 minutes, it considers it to be dead or out of place, and starts replication of blocks that were hosted on that data node such that they are hosted on some other data node.A BlockReport contains list of all blocks on a DataNode. Now, the system starts to replicate what were stored in dead DataNode.
    The NameNode manages the replication of data blocksfrom one DataNode to other. In this process, the replication data transfers directly between DataNode such that the data never passes the NameNode.
9.What are the core methods of a Reducer?
    The three core methods of a Reducer are:
    1. setup(): this method is used for configuring various parameters like input data size, distributed cache.
    public void setup (context)
    2. reduce(): heart of the reducer always called once per key with the associated reduced task
    public void reduce(Key, Value, context)
    3. cleanup(): this method is called to clean temporary files, only once at the end of the task
    public void cleanup (context)
10.What is SequenceFile in Hadoop?
    Extensively used in MapReduce I/O formats, SequenceFile is a flat file containing binary key/value pairs. The map outputs are stored as SequenceFile internally. It provides Reader, Writer and Sorter classes. The three SequenceFile formats are:
    1. Uncompressed key/value records.
    2. Record compressed key/value records – only ‘values’ are compressed here.
    3. Block compressed key/value records – both keys and values are collected in ‘blocks’ separately and compressed. The size of the ‘block’ is configurable.
11.What is Job Tracker role in Hadoop?
    Job Tracker’s primary function is resource management (managing the task trackers), tracking resource availability and task life cycle management (tracking the taks progress and fault tolerance).
    • It is a process that runs on a separate node, not on a DataNode often
    • Job Tracker communicates with the NameNode to identify data location
    • Finds the best Task Tracker Nodes to execute tasks on given nodes
    • Monitors individual Task Trackers and submits the overall job back to the client.
    • It tracks the execution of MapReduce workloads local to the slave node.
12.What is the use of RecordReader in Hadoop?
    Since Hadoop splits data into various blocks, RecordReader is used to read the slit data into single record. For instance, if our input data is split like:
    Row1: Welcome to
    Row2: Intellipaat
    It will be read as “Welcome to Intellipaat” using RecordReader.
13.What is Speculative Execution in Hadoop?
    One limitation of Hadoop is that by distributing the tasks on several nodes, there are chances that few slow nodes limit the rest of the program. Tehre are various reasons for the tasks to be slow, which are sometimes not easy to detect. Instead of identifying and fixing the slow-running tasks, Hadoop tries to detect when the task runs slower than expected and then launches other equivalent task as backup. This backup mechanism in Hadoop is Speculative Execution.
    It creates a duplicate task on another disk. The same input can be processed multiple times in parallel. When most tasks in a job comes to completion, the speculative execution mechanism schedules duplicate copies of remaining tasks (which are slower) across the nodes that are free currently. When these tasks finish, it is intimated to the JobTracker. If other copies are executing speculatively, Hadoop notifies the TaskTrackers to quit those tasks and reject their output.
    Speculative execution is by default true in Hadoop. To disable, set mapred.map.tasks.speculative.execution and mapred.reduce.tasks.speculative.execution
    JobConf options to false.
14.What happens if you try to run a Hadoop job with an output directory that is already present?
    It will throw an exception saying that the output file directory already exists. To run the MapReduce job, you need to ensure that the output directory does not exist before in the HDFS.  To delete the directory before running the job, you can use shell:Hadoop fs –rmr /path/to/your/output/Or via the Java API: FileSystem.getlocal(conf).delete(outputDir, true);

15.How can you debug Hadoop code?
    First, check the list of MapReduce jobs currently running. Next, we need to see that there are no orphaned jobs running; if yes, you need to determine the location of RM logs.
    1. Run: “ps –ef | grep –I ResourceManager”
    and look for log directory in the displayed result. Find out the job-id from the displayed list and check if there is any error message associated with that job.
    2. On the basis of RM logs, identify the worker node that was involved in execution of the task.
    3. Now, login to that node and run – “ps –ef | grep –iNodeManager”
    4. Examine the Node Manager log. The majority of errors come from user level logs for each map-reduce job.
16.How to configure Replication Factor in HDFS?
    hdfs-site.xml is used to configure HDFS. Changing the dfs.replication property in hdfs-site.xml will change the default replication for all files placed in HDFS.
    You can also modify the replication factor on a per-file basis using the Hadoop FS Shell:[training@localhost ~]$ hadoopfs –setrep –w 3 /my/fileConversely, you can also change the replication factor of all the files under a directory.
    [training@localhost ~]$ hadoopfs –setrep –w 3 -R /my/dir

17.How to compress mapper output but not the reducer output?
    To achieve this compression, you should set:
    conf.set(“mapreduce.map.output.compress”, true)
    conf.set(“mapreduce.output.fileoutputformat.compress”, false)
18.What is the difference between Map Side join and Reduce Side Join?
    Map side Join at map side is performed data reaches the map. You need a strict structure for defining map side join. On the other hand, Reduce side Join (Repartitioned Join) is simpler than map side join since the input datasets need not be structured. However, it is less efficient as it will have to go through sort and shuffle phases, coming with network overheads.
19.How can you transfer data from Hive to HDFS?

By writing the query: hive> insert overwrite directory ‘/’ select * from emp;
You can write your query for the data you want to import from Hive to HDFS. The output you receive will be stored in part files in the specified HDFS path.

20.What companies use Hadoop, any idea?
Yahoo! (the biggest contributor to the creation of Hadoop) – Yahoo search engine uses Hadoop, Facebook – Developed Hive for analysis , Amazon, Netflix, Adobe, eBay, Spotify, Twitter, Adobe.

Internet of Things

Internet of Things definition: The vast network of devices connected to the Internet, including smart phones and tablets and almost anything with a sensor on it – cars, machines in production plants, jet engines, oil drills, wearable devices, and more. These “things” collect and exchange data.
IoT – and the machine-to-machine (M2M) technology behind it – are bringing a kind of “super visibility” to nearly every industry. Imagine utilities and telcos that can predict and prevent service outages, airlines that can remotely monitor and optimize plane performance, and healthcare organizations that can base treatment on real-time genome analysis. The business possibilities are endless. 

What is the current state of security in IoT products on the consumer scale, such as household appliances, wearables, smart-home systems, etc.?

Smart watches: A recent HP study revealed security and privacy issues in all of the top 10 smart watch brands. Issues include lack of transport encryption, automatic connectivity to any Bluetooth device within range, and problems with lock down screens.
Smart home systems: These systems show many problems, including not encrypting data and having weak password policies.
Smart TVs: Some brands leave data vulnerable in transit. For example, in 2015, researchers discovered some Samsung smart TVs were sending unencrypted voice recognition data and text information.
All of these connected devices share data with mobile phones and tablets, and are often programmed to automatically connect to any Bluetooth or Wi-Fi network. And, anytime a device is connected to a "public" network, there are risks involved (e.g., data theft and sabotage). This automatic connection feature makes these devices vulnerable when connecting to any "public" network.

Why are there such poor security practices in IoT products?

Lack of understanding and devotion to good security protocols.
Manufacturing engineers and developers are usually more interested in making sure the product works and is launched on schedule, rather than making sure these devices are secure.
In order to compete in the market, many of these products are designed with an emphasis on keeping the cost as low as possible. Stronger security implementation isn't prioritized properly, because it typically doesn't reduce the cost of producing a product.
Many IoT devices lack the computing power of a desktop or laptop computer, or other higher-end devices, which makes it difficult to implement strong security.
A cultural divide exists between InfoSec professionals (those concerned with keeping the communications between devices secure), and mechanical and electrical engineers (those concerned with the switches, motors, etc., making sure the devices operate). InfoSec as an industry needs to do a better job of reaching out to build relationships with the engineers, and better demonstrate the value of security more effectively to bridge that cultural divide.

How do we best address the technical challenges impacting security for the IoT?

The security industry can do this in several ways, but it starts with recognizing the problems and then providing better education about the solutions.
In most cases, the technology is available and just needs to be implemented. For example, SSL/TLS provides strong and scalable encryption at the scale that the IoT demands. Sophisticated, managed PKI systems can handle strong identity vetting and provide reliable data encryption across all objects and devices within IoT deployments. A PKI solution should be the standard for IoT.
The security industry needs to help vendors understand the risks associate with poor IoT security. First, we need to present information from the point-of-view of an end-user. Second, organizations need to be made aware of the financial impact of poor security: lowered sales, diminished trust in their brand, or even health and safety risks when healthcare devices, critical infrastructure, and national defense are included in the conversation.
Simple protections can be put in place that notify end-users to set up controls over Wi-Fi and Bluetooth connectivity, enabling lock screens, and other basic security functions.

How can an organization implement a trusted IoT security framework?

First, an organization needs to choose a Certificate Authority partner that is trusted and can scale effectively to meet their IoT requirements.
Second, manufacturers need to embed identity in devices during OEM rollout process. Third, they need to utilize regulated Attribute Authorities.
Finally, they shouldn't rely on established technology alone; they should integrate technology and tokens, adopt policies and procedures for accountability purposes, and review relationships and responsibilities regularly.

Industry 4.0- the fourth industrial revolution

What is Industry 4.0?

Industry 4.0 (sometimes referred to as the fourth industrial revolution) is the move towards digitisation of the manufacturing sector. Manufacturing technologies such as The Internet of Things (IoT), cyber-physical systems, big data, advanced analytics, human-machine interfaces, cloud computing, all communicate with each other in real-time to form the fourth industrial revolution.
The data produced from such automated systems can be exchanged easily and quickly acted upon. Many of these technologies are already present in businesses, but in the coming years will become more relevant.

Where did it originate from?
The term Industrie 4.0 was first used in March 2012 as a reference in a ‘future project’ listed within the High-Tech Strategy 2020 Action Plan, which was approved by the German government. To remain at the forefront of this technological race, the German government is reportedly investing approximately €200 million (£140 million) in Industry 4.0 research involving academia, businesses and government.
The rest of the world are now taking note such as the US, who has formed a Smart Manufacturing Leadership Coalition (SMLC), comprising of manufacturers, suppliers, technology firms, and government - with the objective of advancing the thinking behind Industry 4.0.

When does it start?
It’s been evolving for some time now. You can’t buy it, download it or subscribe to it. When businesses start to connect existing processes together, install digital equipment and generate big data analytics to improve data efficiency, then Industry 4.0 will be in full swing.

Where does the Internet of Things fit in?
The Fourth Industrial Revolution is enabled by technologies such as the Internet of Things (IoT), big data and connectivity. The connectivity of equipment, people, processes and supply chains all make up the Internet of Things (IoT) and Industry 4.0.

The emergence of this new era of embedded technology means that information on how these things are integrated together is available at your fingertips.

What does it mean for manufacturers?
The way products and services are consumed is changing so much, as demands for customized goods is ever increasing. Manufacturers have to respond quickly to these changing market conditions and in the most efficient way. Having a smart, connected factory will be an enabler of this.

So with all the Industry 4.0 craze, manufacturers will be wondering what it will mean for their businesses. None will want to be left behind, so to stay ahead of the game some manufacturers will change their processes and equipment, and adapt new strategies and business models to embrace Industry 4.0.

Adopting key Industry 4.0 technologies as soon as possible to become the leading force in your industry will help your business react quickly to market changes, respond to current and new competitors, and inevitably future proof manufacturing operations, drive sustainable growth and innovation.

What are the opportunities for manufacturers?
Being at the forefront of Industry 4.0 and taking advantage of technology will allow manufacturers, big or small to achieve business outcomes that weren’t possible 10 years ago, such as improving cost-effectiveness and product quality.

IoT enabled technologies will give manufacturers the chance to have full visibility of operations and allow them to be responsive to information about raw materials, inventory, quality, waste, output and customer demands, ensuring that opportunities for improvement are highlighted and action is taken, saving money, time and improving customer satisfaction and supplier relations.

What challenges could manufacturers face?
The workforce dynamics will change as employees adapt to new technologies and processes. Engineers are the facilitators, and management will need to know what information is needed to be collected to make the factory operate more effectively. IoT is about integration and making things talk which largely doesn’t happen automatically, people are the key to making it happen!

SMAC (Social, Mobile, Analytics and Cloud)

SMAC (social, mobile, analytics and cloud) is the concept that four technologies are currently driving business innovation.

SMAC creates an ecosystem that allows a business to improve its operations and get closer to the customer with minimal overhead and maximum reach. The proliferation of structured and unstructured data that is being created by mobile devices, sensors, social media, loyalty card programs and website browsing is creating new business models built upon customer-generated data. None of the four technologies can be an afterthought because it's the synergy created by social, mobile, analytics and cloud working together that creates a competitive advantage.

Social media has provided businesses with new ways to reach and interact with customers, while mobile technologies have changed the way people communicate, shop and work. Analytics allow businesses to understand how, when and where people consume certain goods and services and cloud computing provides a new way to access technology and the data a business needs to quickly respond to changing markets and solve business problems. While each of the four technologies can impact a business individually, their convergence is proving to be a disruptive force that is creating entirely new business models for service providers.

The integration of the technologies requires clear policies and guidelines as well as management tools that can automate business processes. The media company Netflix is often cited as an example of a business that has successfully harnessed the power of SMAC. For example, when a Netflix member streams a TV show from the Netflix cloud to their iPad, they are given the option of signing into Netflix with Facebook's social login. After viewing a show, members are given multiple ways to provide social feedback. They can rate content with stars, write reviews and/or share what they just watched with friends on Facebook or Twitter. Customer data is stored in the cloud and Netflix can break down its analysis to such a granular a level that its recommendation engine can personalize suggestions for individual family members who share the same account, a concept known as 1:1 marketing.

Networking sites for software developers

HTML5 Rocks (https://www.html5rocks.com/en/)- HTML5 Rocks is an open source project from Google. It is a site for developers dedicated to HTML5 where they can find resources, tutorials and demonstrations of the technology. Anyone can become a contributor of the community.

Forrst (http://forrst.com/)- Forrst is a forum for Web designers and developers where they can share designs and code to get feedback from other designers and developers, or write posts about designtopics and ultimately getting better at their craft. It also offers an About.me-like profile page for designers called Forrst.me. Users can make public posts and share them with non-users. Forrst is an Invite only community.

GitHub (https://github.com/)- GitHub is a web-based hosting service for software development projects. Originally born as a project to simplify sharing code, GitHub has grown into the largest code host in the world. GitHub offers both commercial plans and free accounts for open source projects.

Geeklist- Geekli.st is an achievement-based social portfolio builder for developers where they can communicate with colleagues and employers and build credibility in the workplace.

Snipplr(http://snipplr.com/)- Snipplr was designed to solve the problem of having too many random bits of code and HTML scattered all over computers. Basically it's a place to keep code snippets stored in one place for a better organization and access to them. Also, user's can access each others' code librarys. It allows its users to make their code accessible from any aomputer and easier to share.

Masterbranch(https://masterbranch.com/)- Masterbranch is a site for developers and employers. Developers can create their coding profile, and employers who are looking for great developers can find candidates for available positions.

Bisquits (http://www.bisquits.net/)- Bisquits is a social network for developers, which allows them to create, find and save codes in a personal library.  The site is still in beta, but online. It is an invitation only service.

Codesnipp.it- Codesnipp.it is a social sharing site for developers where they can post, categorize and tag pieces of code, plugins, or anything developer related they'd like to share. Users can also follow other members and follow their timelines.Subscription is free, but users can upgrade their account to premium to get unlimited posting and have access to a private area.

Stackoverflow (http://stackoverflow.com/)- Stack Overflow is a free programming Q & A site. Stack Overflow is collaboratively built and maintained by its members.

Bettercodes- Bettercodes is an open source community for developers to share their ideas and turn them into code that works. The site's aim is to connect like-minded developers to collaborate on code-related projects.

Android developers network- https://developer.android.com/training/basics/network-ops/connecting.html

iOS developers network- https://developer.apple.com/library/content/documentation/NetworkingInternetWeb/Conceptual/NetworkingOverview/Introduction/Introduction.html

Sun Java developers network- http://www.oracle.com/technetwork/java/index.html

.NET developers network- https://msdn.microsoft.com/en-us/library/ff361664(v=vs.110).aspx

Six Sigma Interview Questions and Answers-1

Q1. When and by whom was six sigma developed ?

Ans. In 1986 Six Sigma was developed by Motorola.


Q2. Explain six sigma’s purpose.

Ans. Six sigma’s purpose is to identify the causes of defects and errors and then remove them in the manufacturing process.

Q3. What is the symbol of Six sigma ?

Ans. Six Sigma has a greek symbol which is ”sigma”. It is the standard deviation utilized to measure the variation in the process.

Q4. Six sigma uses two key methods. What are they?

Ans. They are DMAIC and DMADV

Q5. What does DMAIC stands for in six sigma ?

Ans. DMAIC is an abbreviation for define, measure, analyze, improve and control.


Q6. What does DMADV stands for in six sigma ?

Ans. DMADV is an abbreviation for define,measure,analyze,develop,verify


Q7. Have you seen Six Sigma jobs being advertised under many titles ?

Ans.Six Sigma jobs are advertised under many titles,not always as obvious as Six Sigma Black Belt,Six Sigma Consultant or Six Sigma Analyst.Other possible titles include things like Functional Project Lead Six Sigma Program Manager,Lead Analyst/Project Manager,Director of Operational Excellence, Business Process Manager or Senior Projects Manager.Whatever the exact title, the organization is looking for someone with the skills of a Six Sigma Black Belt.

Q8. Explain scope of your future in six sigma type job ?

Ans. You need to be able to demonstrate a good understanding of processes and quality methodologies and a willingness to take an initiative and lead change. Another crucial skill is the ability to link strategy to execution.


Q9. Exlain the quality levels of Six sigma ?

Ans. Six Sigma quality levels are 99.9996% accurate and also they have only 3.4 defects per million opportunities.

Q10. Explain key roles in all Six Sigma efforts ?

Ans.  The following are the key roles of Six Sigma efforts:

Sponsor: Business executive leading the organization.

Champion: Responsible for Six Sigma strategy, deployment, and vision.

Process Owner: Owner of the process, product, or service being improved responsible for long-term sustainable gains.

Master Black Belts: Coach black belts expert in all statistical tools.

Black Belts: Work on 3 to 5 $250,000-per-year projects; create $1 million per year in value.

Green Belts: Work with black belt on projects.

Q11. Explain MAIC in six sigma ?

Ans. The following explains the MAIC :

Measure: Problem assessment by gathering right information.

Analyze: Indentify root cause of problem by using statistical tools.

Improve: Solve the problem (not the symptom).

Control: Put a plan in place to make a check that problems stay fixed and sustain the gains.

Q12. How should company integrate lean into six sigma ?

Ans.  Lean takes the waste out of an area six sigma resolves the issue

Q13. Differentiate between load test and performance testing?

Ans. More stress is involved in performance testing, on system and checks whether the system performance is same as the less stress condition. Where as in load testing the stress is kept beyond the limit specified by the client.Performance testing is the super set of load testing. Load testing involves the testing process which determines how well the system is capable for handling concurrent users or the load. Where as performance testing includes the load as well as the stress testing.


Q14. Explain Load testing process ?

Ans. The following steps explains the Load testing process :

Plan the test. A clear test plan is required for ensuring the test scenarios to accomplish the objectives of load testing

Creation of Vusers. Vusers scripts are created that contains the tasks performed by each and every Vuser and all Vuser tasks collectively as a whole.

Creation of scenario. Describing the events that occurred in the testing. This process includes the list machines, scripts, and Vusers which run during the scenario. The Load Runner controller is used for creation of automatic scenarios.

Q15. Mention the list of acceptable number of defects per million corresponding to each Sigma level ?

Ans. Following information mentions the acceptable number of defects per million to correspond to each Sigma level:

Sigma level               Defects per million opportunities

1                                                690,000

2                                                308,527

3                                                66,817

4                                                6,220

5                                                232

6                                                3.4



Q16. Explain the concept of standard deviation?

Ans. Standard deviation quantifies the variation most accurately indicating the degree of variation in a set of measurement or a process by measuring the average spread of data around the mean. It provides accurate information.

iOS Interview Questions & Answers-1

1) Explain what is Xcode?

Xcode is Apple’s integrated development environment (IDE) that you use to design apps for Apple products.  It provides various tools to manage your entire development workflow from creating your app, to testing, submitting and optimizing it to the App store.

2) Explain what is struct?

A struct is a special C data type that encapsulates other pieces of data into a single cohesive unit.

3) Explain how you can add frameworks in Xcode project?

To add frameworks in Xcode project

    Choose the project file from the project navigator on the left side of the project window
    Choose the target where you want to add frameworks in the project settings editor
    Choose the “Build Phases” tab, and select the small triangle next to “Link Binary With Libraries” to view all of the frameworks in your application
    To add frameworks click on “+” sign below the list of frameworks
    To choose multiple frameworks, press and hold the command key while choosing the framework

4) Mention what is the difference between bounds and frame?

    Frame: The frame of a view is the rectangle, represented as a location (X, Y) and size (width, height) corresponding to the superview it is contained within
    Bounds: The bounds of a view is the rectangle, represented as a location (X, Y) and size (width, height) corresponding to its own co-ordinate system (0,0)

5) Explain what is the difference between Xcode, Cocoa and Objective C?

    Xcode: It is the integrated development environment (IDE) that developer use to write software for IOS or OS X.
    Objective-C: It is the language most preferred by developer to write programs for apple
    Cocoa: It is the application

Logo_xcode

6) Explain what is Xcode command line tools package?

Command line tools package is a self-contained package available separately from Xcode. It enables you to do command line development in OS X.  It consists of two components like command line tools such as Clang and OS X SDK.

7) Mention what are the new features in Xcode 6?

In Xcode 6,  new features include

    Support for Swift: Xcode 6 explicitly supports the Swift code, it is very simple and easy to make a brand new app using 100% swift code to existing frameworks.
    Playgrounds: It enables the interactive experience of a scripting language, like you can show variables in a graph, watch an animated SpriteKit Scene or inspect each step when drawing a view. Once you are done with code in the playground, you can move it into your project
    Command Line: You can use Swift syntax to interact and evaluate with your running app or write new code in a script like environment
    Performance Testing: The XCTest framework is extended to support performance test, and is completely synchronized with Xcode and Xcode Server. It also raises alerts for regression when test results change
    View Debugging: Xcode allows easy debugging and includes new debugging tools like debug gauges to monitor I/O usage and enhance iCloud gauge

8) Mention what is the use of PO command in Xcode?

PO command is useful during debug time. In normal scenario, to print the value of a variable, you have to move the mouse pointer there and select print description print value of it.  With PO command, you can print value by just writing the “PO variable name” in output window, and press enter.

9) Mention what are the two different smart groups in Xcode?

Simple smart groups are classified into two categories

    Simple filter smart group: It matches files based on file name “globbing” used in the shell
    Simple expression smart group: It matches files using regular expression

10) Explain how you can delete a smart group created in Xcode?

It is not possible to delete smart groups individually, so you can delete smart group in Xcode either by

    Deleting all the smart groups saved in an individual project
    Or by deleting all the global smart groups available in the project

11) Explain how you can migrate to Xcode?

To migrate to Xcode you need to import your ProjectBuilderWO projects into Xcode by following steps

    Select file -> Import project -> Open the import project assistant
    From the import project assistant, select the import projectBuilderWO projects and tap on the next button
    Choose the button to select the project document
    Enter the name you want to use for the new Xcode project in the New Project Name Field and click finish

12) Mention what are the source items used by Xcode?

Xcode uses four different types of source items

    Source File
    Source Group
    Source Folder
    Framework

13) What is the short cut to open the “Code Snippet Library” in Xcode?

(CMD+OPT+Cntrl+2) is the short-cut to open the “Code Snippet Library” in Xcode.

14) Mention the short-cut to edit variables in Scope?

To edit variables in Scope, you can use the command Cntrl+cmd+E.

15) Mention what are the build phases available in Xcode?

There are three build phases in Xcode that is available by default

    Compile Sources
    Link binary with libraries
    Copy bundle resources

16) Explain how app delegate is declared by Xcode project templates?

App delegate is defined as a sub-class of UIResponder by Xcode project templates.

17) Mention what are all instruments available in Xcode?

To trace and profile Mac OS X and iOS code an application is used referred as Instruments. It allows you to track one or more than one processes and analyze the collected data.  It helps you to understand the behavior of both operating system and the user programs.

18) Explain what does @synthesize do?

Keyword @synthesize tell the compiler that it should create the setter or getter for the property if you do not supply them with the @implementation block.

19) Explain what is Swift Programming Language?

Swift is a programming language and system for creating applications for iOS and OS X. It is an innovative programming language for Cocoa and Cocoa Touch.

20) Explain how you define variables in Swift language?

Variables and constants must be declared before they are used. You announce constants with the let keyword and variables with the var keyword. Both variables and dictionaries are described using brackets. For example,

Var  Guru99 = “This is Guru99”

Let ksomeconstant = 30

21) Explain how Swift program is deployed?

Swift program deploys the application in a Tomcat installation by default. The deploy script bundles the client code into JavaScript, gathers all the server side classes required and packages them into file Hello.war. This file together with a GWT jar and a Swift runtime jar is copied into the Tomcat installation. If CATALINA_HOME is not set, these files require to be copied manually.

22) Mention what are the features of Swift Programming?

    It eliminates entire classes of unsafe code
    Variables are always initialized before use
    Arrays and integers are checked for overflow
    Memory is managed automatically
    Instead of using “if” statement in conditional programming, swift has “switch” function

23) Mention what is the difference between Swift and ‘Objective-C’ language?

Difference between ‘C’ and ‘Swift’ language is that
Swift    Objective-C

    In a swift, the variable and constants are declared before their use
    You have to use “let” keyword for constant and “var” keyword for variable
    There is no need to end code with semi-colon
    Concatenating strings is easy in swift and allows to make a new string from a mix of constants,  literals, variables, as well as expressions
    Swift does not require to create a separate interface like Objective C. You can define classes in a single file (.swift)
    Swift enables you to define methods in class, structure or enumeration
    In Swift, you use “ +=” Operator to add an item

   

    In objective C, you have to declare variable as NSString and constant as int
    In objective C, variable is declared as “ and constant as “
    The code ends with semi-colon
    In objective C, you have to choose between NSMutableString and NSString for string to be modified.
    For classes, you create separate interface (.h) and implementation (.m) files for classes
    Objective does not allow this
    In C, you use “addObject”: method of NSMutable array to append a new item to an array

iOS-Swift-Logo

24) Mention what are the type of integers does Swift have?

Swift provides unsigned and signed integers in 8, 16, 32 and 64 bit forms. Similar to C these integers follow a naming convention. For instance, unsigned integer is denoted by type UInt8 while 32 bit signed integer will be denoted by type Int32.

25) Mention what is the Floating point numbers and what are the types of floating number in Swift?

Floating numbers are numbers with a fractional component, like 3.25169 and -238.21.  Floating point types can represent a wider range of values than integer types. There are two signed floating point number

    Double: It represents a 64 bit floating point number, it is used when floating point values must be very large
    Float: It represents a 32 bit floating point number, it is used when floating point values does not need 64 bit precision

26) Explain how multiple line comment can be written in swift?

Multiple line comment can be written as forward-slash followed by an asterisk (/*)  and end with an asterisk followed by a forward slash (*/).

27) What is de-initializer and how it is written in Swift?

A de-initializer is declared immediately before a class instance is de-allocated.  You write de-initializer with the deinit keyword.  De-initializer is written without any parenthesis, and it does not take any parameters. It is written as

deinit  {

// perform the deinitialization

}

28) Mention what are the collection types available in Swift?

In Swift, collection types come in two varieties Array and Dictionary

    Array: You can create an Array of a single type or an array with multiple types. Swift usually prefers the former one

Example for single type array is,

Var cardName : [String] = [ “Robert” , “Lisa” , “Kevin”]

// Swift can infer [String] so we can also write it as:

Var cardNames = [ “Robert”, “Lisa”, “Kevin”] // inferred as [String]

To add an array you need to use the subscript println(CardNames[0])

    Dictionary: It is similar to a Hash table as in other programming language. A dictionary enables you to store key-value pairs and access the value by providing the key

var cards = [ “Robert”: 22, “Lisa” : 24, and “Kevin”: 26]

29) List out what are the control transfer statements used in Swift?

Control transfer statements used in Swift includes

    Continue
    Break
    Fallthrough
    Return

30) Explain what is optional chaining?

Optional chaining is a process of querying and calling properties. Multiple queries can be chained together, and if any link in the chain is nil then, the entire chain fails.

31) How base-class is defined in Swift?

In Swift the classes are not inherited from the base class and the classes that you define without specifying its superclass, automatically becomes the base-class.

32) Explain what Lazy stored properties is and when it is useful?

Lazy stored properties are used for a property whose initial values is not calculated until the first time it is used.  You can declare a lazy stored property by writing the lazy modifier before its declaration. Lazy properties are useful when the initial value for a property is reliant on outside factors whose values are unknown.

33) Mention what is the characteristics of Switch in Swift?

    It supports any kind of data, and not only synchronize but also checks for equality
    When a case is matched in switch, the program exists from the switch case and does not continue checking next cases. So you don’t need to explicitly break out the switch at the end of case
    Switch statement must be exhaustive, which means that you have to cover all possible values for your variable
    There is no fallthrough in switch statements and therefore break is not required

Android Interview Questions and Answers-1

1) What is Android?

It is an open-sourced operating system that is used primarily on mobile devices, such as cell phones and tablets. It is a Linux kernel-based system that’s been equipped with rich components that allows developers to create and run apps that can perform both basic and advanced functions.

2) What Is the Google Android SDK?

The Google Android SDK is a toolset that developers need in order to write apps on Android enabled devices. It contains a graphical interface that emulates an Android driven handheld environment, allowing them to test and debug their codes.

3) What is the Android Architecture?

Android Architecture is made up of 4 key components:
– Linux Kernel
– Libraries
– Android Framework
– Android Applications

4) Describe the Android Framework.

Android Interview Questions

The Android Framework is an important aspect of the Android Architecture. Here you can find all the classes and methods that developers would need in order to write applications on the Android environment.

5) What is AAPT?

AAPT is short for Android Asset Packaging Tool. This tool provides developers with the ability to deal with zip-compatible archives, which includes creating, extracting as well as viewing its contents.

6) What is the importance of having an emulator within the Android environment?

The emulator lets developers “play” around an interface that acts as if it were an actual mobile device. They can write and test codes, and even debug. Emulators are a safe place for testing codes especially if it is in the early design phase.

7) What is the use of an activityCreator?

An activityCreator is the first step towards the creation of a new Android project. It is made up of a shell script that will be used to create new file system structure necessary for writing codes within the Android IDE.

8 ) Describe Activities.

Activities are what you refer to as the window to a user interface. Just as you create windows in order to display output or to ask for an input in the form of dialog boxes, activities play the same role, though it may not always be in the form of a user interface.

9) What are Intents?

Intents displays notification messages to the user from within the Android enabled device. It can be used to alert the user of a particular state that occurred. Users can be made to respond to intents.

10) Differentiate Activities from Services.

Activities can be closed, or terminated anytime the user wishes. On the other hand, services are designed to run behind the scenes, and can act independently. Most services run continuously, regardless of whether there are certain or no activities being executed.

11) What items are important in every Android project?

These are the essential items that are present each time an Android project is created:
– AndroidManifest.xml
– build.xml
– bin/
– src/
– res/
– assets/

12) What is the importance of XML-based layouts?

The use of XML-based layouts provides a consistent and somewhat standard means of setting GUI definition format. In common practice, layout details are placed in XML files while other items are placed in source files.

13) What are containers?

Containers, as the name itself implies, holds objects and widgets together, depending on which specific items are needed and in what particular arrangement that is wanted. Containers may hold labels, fields, buttons, or even child containers, as examples.

14) What is Orientation?

Orientation, which can be set using setOrientation(), dictates if the LinearLayout is represented as a row or as a column. Values are set as either HORIZONTAL or VERTICAL.

15) What is the importance of Android in the mobile market?

Developers can write and register apps that will specifically run under the Android environment. This means that every mobile device that is Android enabled will be able to support and run these apps. With the growing popularity of Android mobile devices, developers can take advantage of this trend by creating and uploading their apps on the Android Market for distribution to anyone who wants to download it.

16) What do you think are some disadvantages of Android?

Given that Android is an open-source platform, and the fact that different Android operating systems have been released on different mobile devices, there’s no clear cut policy to how applications can adapt with various OS versions and upgrades. One app that runs on this particular version of Android OS may or may not run on another version. Another disadvantage is that since mobile devices such as phones and tabs come in different sizes and forms, it poses a challenge for developers to create apps that can adjust correctly to the right screen size and other varying features and specs.

17) What is adb?

Adb is short for Android Debug Bridge. It allows developers the power to execute remote shell commands. Its basic function is to allow and control communication towards and from the emulator port.

18) What are the four essential states of an activity?

– Active – if the activity is at the foreground
– Paused – if the activity is at the background and still visible
– Stopped – if the activity is not visible and therefore is hidden or obscured by another activity
– Destroyed – when the activity process is killed or completed terminated

19) What is ANR?

ANR is short for Application Not Responding. This is actually a dialog that appears to the user whenever an application have been unresponsive for a long period of time.

20) Which elements can occur only once and must be present?

Among the different elements, the and elements must be present and can occur only once. The rest are optional, and can occur as many times as needed.

21) How are escape characters used as attribute?

Escape characters are preceded by double backslashes. For example, a newline character is created using ‘\\n’

22) What is the importance of settings permissions in app development?

Permissions allow certain restrictions to be imposed primarily to protect data and code. Without these, codes could be compromised, resulting to defects in functionality.

23) What is the function of an intent filter?

Because every component needs to indicate which intents they can respond to, intent filters are used to filter out intents that these components are willing to receive. One or more intent filters are possible, depending on the services and activities that is going to make use of it.

24) Enumerate the three key loops when monitoring an activity

– Entire lifetime – activity happens between onCreate and onDestroy
– Visible lifetime – activity happens between onStart and onStop
– Foreground lifetime – activity happens between onResume and onPause

25) When is the onStop() method invoked?

A call to onStop method happens when an activity is no longer visible to the user, either because another activity has taken over or if in front of that activity.

26) Is there a case wherein other qualifiers in multiple resources take precedence over locale?

Yes, there are actually instances wherein some qualifiers can take precedence over locale. There are two known exceptions, which are the MCC (mobile country code) and MNC (mobile network code) qualifiers.

27) What are the different states wherein a process is based?

There are 4 possible states:
– foreground activity
– visible activity
– background activity
– empty process

28) How can the ANR be prevented?

One technique that prevents the Android system from concluding a code that has been responsive for a long period of time is to create a child thread. Within the child thread, most of the actual workings of the codes can be placed, so that the main thread runs with minimal periods of unresponsive times.

29) What role does Dalvik play in Android development?

Dalvik serves as a virtual machine, and it is where every Android application runs. Through Dalvik, a device is able to execute multiple virtual machines efficiently through better memory management.

30) What is the AndroidManifest.xml?

This file is essential in every application. It is declared in the root directory and contains information about the application that the Android system must know before the codes can be executed.

31) What is the proper way of setting up an Android-powered device for app development?

The following are steps to be followed prior to actual application development in an Android-powered device:
-Declare your application as “debuggable” in your Android Manifest.
-Turn on “USB Debugging” on your device.
-Set up your system to detect your device.

32) Enumerate the steps in creating a bounded service through AIDL.

1. create the .aidl file, which defines the programming interface
2. implement the interface, which involves extending the inner abstract Stub class as well as implanting its methods.
3. expose the interface, which involves implementing the service to the clients.

33) What is the importance of Default Resources?

When default resources, which contain default strings and files, are not present, an error will occur and the app will not run. Resources are placed in specially named subdirectories under the project res/ directory.

34) When dealing with multiple resources, which one takes precedence?

Assuming that all of these multiple resources are able to match the configuration of a device, the ‘locale’ qualifier almost always takes the highest precedence over the others.

35) When does ANR occur?

The ANR dialog is displayed to the user based on two possible conditions. One is when there is no response to an input event within 5 seconds, and the other is when a broadcast receiver is not done executing within 10 seconds.

36) What is AIDL?

AIDL, or Android Interface Definition Language, handles the interface requirements between a client and a service so both can communicate at the same level through interprocess communication or IPC. This process involves breaking down objects into primitives that Android can understand. This part is required simply because a process cannot access the memory of the other process.

37) What data types are supported by AIDL?

AIDL has support for the following data types:
-string
-charSequence
-List
-Map
-all native Java data types like int,long, char and Boolean

38) What is a Fragment?

A fragment is a part or portion of an activity. It is modular in a sense that you can move around or combine with other fragments in a single activity. Fragments are also reusable.

39) What is a visible activity?

A visible activity is one that sits behind a foreground dialog. It is actually visible to the user, but not necessarily being in the foreground itself.

40) When is the best time to kill a foreground activity?

The foreground activity, being the most important among the other states, is only killed or terminated as a last resort, especially if it is already consuming too much memory. When a memory paging state has been reach by a foreground activity, then it is killed so that the user interface can retain its responsiveness to the user.

41) Is it possible to use or add a fragment without using a user interface?

Yes, it is possible to do that, such as when you want to create a background behavior for a particular activity. You can do this by using add(Fragment,string) method to add a fragment from the activity.

42) How do you remove icons and widgets from the main screen of the Android device?

To remove an icon or shortcut, press and hold that icon. You then drag it downwards to the lower part of the screen where a remove button appears.

43) What are the core components under the Android application architecture?

There are 5 key components under the Android application architecture:
– services
– intent
– resource externalization
– notifications
– content providers

44) What composes a typical Android application project?

A project under Android development, upon compilation, becomes an .apk file. This apk file format is actually made up of the AndroidManifest.xml file, application code, resource files, and other related files.

45) What is a Sticky Intent?

A Sticky Intent is a broadcast from sendStickyBroadcast() method such that the intent floats around even after the broadcast, allowing others to collect data from it.

46) Do all mobile phones support the latest Android operating system?

Some Android-powered phone allows you to upgrade to the higher Android operating system version. However, not all upgrades would allow you to get the latest version. It depends largely on the capability and specs of the phone, whether it can support the newer features available under the latest Android version.

47) What is portable wi-fi hotspot?

Portable Wi-Fi Hotspot allows you to share your mobile internet connection to other wireless device. For example, using your Android-powered phone as a Wi-Fi Hotspot, you can use your laptop to connect to the Internet using that access point.

48) What is an action?

In Android development, an action is what the intent sender wants to do or expected to get as a response. Most application functionality is based on the intended action.

49) What is the difference between a regular bitmap and a nine-patch image?

In general, a Nine-patch image allows resizing that can be used as background or other image size requirements for the target device. The Nine-patch refers to the way you can resize the image: 4 corners that are unscaled, 4 edges that are scaled in 1 axis, and the middle one that can be scaled into both axes.

50) What language is supported by Android for application development?

The main language supported is Java programming language. Java is the most popular language for app development, which makes it ideal even for new Android developers to quickly learn to create and deploy applications in the Android environment.