Core Java Interview Questions
Questions Answers Views Company eMail

What is garbage collection in Java, and how can it be used ?

Infosys, HCL, Accenture, Wipro, Sara, SITS, TCS,

32 59757

Differentiate Vector and ArrayList?

Wipro, Max Telecom,

6 8828

Differentiate constructor and a method and how are it be used?

Wipro,

7 9410




What is an abstract class?

Wipro, DBS,

7 8236

How can final class be used?

Wipro, Accenture,

5 10132

By what default value is an object reference declared as an instance variable?

Wipro,

1 11283

Java support what type of parameter passing ?

Wipro,

7 12707

Explain the term serialization?

Wipro,

10 10569




Is there is any error if you have multiple main methods in the same class?

Wipro, Infosys,

10 11995

What is Overriding and how can it be used?

Consagous, Wipro,

7 14278

Explain pass by reference and pass by value?

IBM, Wipro,

8 12780

In which way does a Primitive data type is passed ?

Sun Microsystems,

5 8426

What happens when a main method is declared as private?

L&T, DELL, Infosys, Sun Microsystems,

22 39230

Is there any need to import java.lang package?

Sun Microsystems,

13 16019

What is UNICODE?

3 4893


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Un-Answered Questions { Core Java }

How we can generate random numbers in java?

17


Can a constructor call the constructor of parent class?

16


What is jit compiler ?

33


What is difference between wait and notify in java?

13


why java uses class level type casting ?

1661






What are the two ways to create a thread?

12


What is method in java ?

21


What about anonymous inner classes in java?

29


What is ‘is-a ‘ relationship in java?

30


define polymorphism in java

39


Can we declare a class as abstract without having any abstract method?

14


There are two classes named classa and classb. Both classes are in the same package. Can a private member of classa can be accessed by an object of classb?

15


Explain how to force the garbage collection in java.

20


Why char array is preferred over string for storing password?

29


What do you mean by aggregation?

16