top 10 java interview questions and answers 2014
DESCRIPTION
What are the top 10 Java Interview Questions and Answers in 2014? Based on the most popular java questions asked in interview, we've compiled a list of the 10 most popular java interview questions in 2014. Appearing for a java interview is not easy but if you brush up enough fundamentals, then you can easily crack the interview. The above questions are the most popular java interview questions asked by major companies so make sure to download this pdf. This list includes java interview questions in the below categories: top 10 java interview questions top 10 java interview questions and answers 10 most popular interview questions core java interview questions and answers basic java interview questions and answers serialization in java interview questions core java interview questions pdf multithreading in java interview questions advanced java interview questions and answers top 10 java interview questions and answers for freshers top 100 java interview questions and answers java interview questions and answers pdf java interview questions and answers for freshers java interview questions and answers for experienced java interview questions and answers for 3 years experience java interview questions and answers pdf download java collections interview questions and answersTRANSCRIPT
TOP 10JAVA INTERVIEW
QUESTIONS &
ANSWERS 2014
SOURCE -> hirist.com
What is JVM?
Why is Java
called the
‘Platform
Independent
Programming
Language’?
#1Java Virtual Machine, is an interpreter which accepts „Bytecode‟ and executes it.
It primarily works on the notion of „compile once, run everywhere‟.
The translation into Bytecode makes a program easier to be executed across a wide range of platforms
JVMs for various platforms might vary in configuration but they all understand the same set of Bytecode
SOURCE -> hirist.com
Which two
methods do
you need to
implement for
key Objects in
HashMap ?
#2
It must implement equals and hashcode method in Java
Equals and hashcode method is used to put and get object from HashMap
SOURCE -> hirist.com
What is
the
Difference
between
JDK and
JRE?
#3The “JDK” is the Java Development Kit. i.e., the JDK is bundle of software that you can use to develop Java based software
The “JRE” is the Java Runtime Environment. I.e., the JRE is an implementation of the Java Virtual Machine which actually executes Java programs.
Each JDK contains one (or more) JRE‟s along with the various development tools like the Java source compilers, bundling and deployment tools, debuggers, development libraries, etc.
SOURCE -> hirist.com
What is
immutable
object? Can
you write
immutable
object?
#4Immutable classes are Java classes whose objects can not be modified once created
Any modification in Immutable object result in a new object
For example, is String is immutable in Java
SOURCE -> hirist.com
What are
the Data
Types
supported
by Java?
#5There are eight Primitive Data types supported by Java
• Byte : 8-bit signed two‟s complement
integer
• Short : 16-bit signed two‟s complement
integer.
• Int : 32-bit signed two‟s complement
integer.
• Long : 64-bit signed two‟s complement
integer.
• Float, Double, Autoboxing, Unboxing
SOURCE -> hirist.com
What is
Autobox
ing and
Unboxin
g?
#6Autoboxing: The Java compiler brings about an automatic transformation of primitive type (int, float, double etc.) into their object equivalents or wrapper type (Integer, Float, Double,etc) for the ease of compilation.
Unboxing: The automatic transformation of wrapper types into their primitive equivalent is known as Unboxing.
SOURCE -> hirist.com
What is
Function
Over-Riding
and Over-
Loading in
Java?
#7Over-Riding: An override is a type of function which occurs in a class which inherits from another class. An override function “replaces” a function inherited from the base class, but does so in such a way that it is called even when an instance of its class is pretending to be a different type through polymorphism.
Over-Loading: Overloading is the action of
defining multiple methods with the same name,
but with different parameters. It is unrelated to
either overriding or polymorphism. Functions in
Java could be overloaded by two mechanisms
ideally:
• Varying the number of arguments.
• Varying the Data Type.
SOURCE -> hirist.com
What is the
difference
between Ar
ray List
and Linked
List ?
#8Array List
- Random access- Only objects can be added
Linked List
- Sequential access- Implemented using nodes linked to each other
SOURCE -> hirist.com
What is
difference
between
CyclicBarrier
and
CountDownLa
tch in Java
#9Main difference between both of them is that you can reuse CyclicBarrier even if Barrier is broken but you cannot reuse CountDownLatch in Java.
SOURCE -> hirist.com
What is
the use of
the
‘SimpleDa
teFormat’
#10SimpleDateFormat is one such concrete class which is widely used by Java developers for parsing and formatting of dates. This is also used to convert Dates to String and vice-versa..
Almost every Enterprise level Java Application invariably uses the SimpleDateFormat for handling user dates
SOURCE -> hirist.com
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