Interview Questions Answers in Core Java

What is Connection pooling? Explain Pros and Cons?

Answer

Connection pooling is the process of resuing the database
connections between application and the server to increase
in the perfaomance of the application.

Is This Answer Correct ?

9 Yes

1 No

Question { 9748 }

What is constructor and virtual function?

Answer

Constructor is a special kind of method used to initialize
an object.

Is This Answer Correct ?

11 Yes

2 No

Question { 12119 }

What is an Exception ?

Answer

An Exception is a mild error conditon that your program
encounters.An Exception can be caught and recoverable.

Is This Answer Correct ?

5 Yes

2 No

Question { 16370 }

What is cloneable interface?

Answer

Cloneable interface is a marker interface which doesn't
have any methods in it.

Is This Answer Correct ?

19 Yes

5 No

Question { 9596 }

What is a default package ?

Answer

java.lang

Is This Answer Correct ?

15 Yes

4 No

Question { 4415 }

What is a native method?

Answer

native method is a method that is implemented in a language
other than java.

Is This Answer Correct ?

3 Yes

0 No

Question { 5927 }

What is a serializable interface?

Answer

Serializable interface is useful if you want to save the
state of a profram to a persistant storage area like file
or database.

Is This Answer Correct ?

0 Yes

0 No

Question { 4140 }

What is unicode?

Answer

unicode is used for the internal representation of
characters and strings and it represents 16 bits to
represents each other.

Is This Answer Correct ?

0 Yes

2 No

Question { 18858 }

What is a void return type?

Answer

it states that the method doesn't return anything.

Is This Answer Correct ?

38 Yes

4 No

Question { 49609 }

What is adapter class?

Answer

Adapter class provides an empty implementation of all the
methods in EventListener interface.

Is This Answer Correct ?

184 Yes

41 No

Question { 4760 }

What is an Iterator interface?

Answer

Iterator provides a general purpose standardised way of
accessing elements one at a time.It has 3 methods
next()
hasNext()
remove()

Is This Answer Correct ?

3 Yes

0 No

Question { 14319 }

What is an abstract class and abstract method?

Answer

Abstract class is a class which contains atleast one
abstract method in it.OTHER methods maybe abstract or
concrete.

Is This Answer Correct ?

15 Yes

0 No

Question { 10833 }

What is finally in exception handling?

Answer

finally is a keyword we have in Exception handling.It
creates a block of code to be executed after try or catch
has completed and before the code following the try or
catch.finally block will be executed whether or not an
exception is thrown.

Is This Answer Correct ?

18 Yes

1 No

Question { 7456 }

What is light weight component?

Answer

swings,threads are light weight components

Is This Answer Correct ?

7 Yes

0 No

Question { 4507 }

What is an Applet ?

Answer

An Applet is a dynamic and interactive program that runs
inside a web page enabled by a java capable browser.

Is This Answer Correct ?

1 Yes

1 No

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