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,

32 52570

Differentiate Vector and ArrayList?

Wipro, Max Telecom,

6 6279

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


6 6819

What is an abstract class?


7 5707

How can final class be used?

Wipro, Accenture,

5 7546

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


1 8790

Java support what type of parameter passing ?


7 10093

Explain the term serialization?


10 8053

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


10 9370

What is Overriding and how can it be used?

Consagous, Wipro,

7 12163

Explain pass by reference and pass by value?

IBM, Wipro,

8 10022

In which way does a Primitive data type is passed ?

Sun Microsystems,

5 6396

What happens when a main method is declared as private?

L&T, DELL, Infosys, Sun Microsystems,

20 30015

Is there any need to import java.lang package?

Sun Microsystems,

13 13160

What is UNICODE?

3 3554

Post New Core Java Questions

Un-Answered Questions { Core Java }

explain the concept of virtual method invocation in polymorphism in detail?


how to deploy tomcatserver to weblogic server? write d following steps?


Why Set interface contains unique elements, what internally implemented for this so that it contains unique elements?


what are the disadvantages of indexes in oracle?


For ease of programming you can consider the maze as a 2D array with colors represented by below integer and characters (in capital letters). • B - Black • W -White • G- Green • R- Red R B W B W W W W W W B W B B W W W W W W W B W B W W W B W W W W B B W W W B W W W B W W B B B B W B W B W W B W W W B W W W B B B W W B W W W B W W B W B W W W B W B W W W W B B W W W W B W W W W W G Shortest Route Problem: • Solution that finds the shortest Route between Red and Green  White will have 1 Weight.  Red and Green carry no weights.  Shortest path is the path with less weight when you add up the weights in the path.


What is files manifesting?


Tell me about your ability to work under pressure


why java uses class level type casting ?


How do you implement polymorphism in our day to day life?




why java does not support unsigned keyword?


what are Hostile Applets?


Write a java program to find the route that connects between Red and Green Cells. General Rules for traversal 1. You can traverse from one cell to another vertically, horizontally or diagonally. 2. You cannot traverse through Black cells. 3. There should be only one Red and Green cell and at least one of each should be present. Otherwise the array is invalid. 4. You cannot revisit a cell that you have already traversed. 5. The maze need not be in the same as given in the above example


os is developed in c no java is more secured then c na why dont the os developed is developed using java


why using interface interface ?