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 48090

Differentiate Vector and ArrayList?

Wipro, Max Telecom,

4 4879

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


6 5358

What is an abstract class?


6 4349

How can final class be used?

Wipro, Accenture,

3 6229

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


1 7454

Java support what type of parameter passing ?


7 8645

Explain the term serialization?


10 6746

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


10 7946

What is Overriding and how can it be used?

Consagous, Wipro,

7 10996

Explain pass by reference and pass by value?

IBM, Wipro,

7 8878

In which way does a Primitive data type is passed ?

Sun Microsystems,

5 5241

What happens when a main method is declared as private?

L&T, DELL, Infosys, Sun Microsystems,

19 23944

Is there any need to import java.lang package?

Sun Microsystems,

13 11481

What is UNICODE?

3 2902

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Un-Answered Questions { Core Java }

java program with complete 4 oops concepts implemented example


how can i use a nonsynchronized hashtable?


if u open login & logout ,how can udisplay the timelogin & logout members ?


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What is Session reduplication and how its done?


What is stored procedure. How do you create stored procedure ?


Draw a UML class diagram for the code fragment given below: public class StringApplet extends Applet { private Label sampleString; private Button showTheString; private ButtonHandler bHandler; private FlowLayout layout; public StringApplet() { sampleString = new Label(" "); showTheString = new Button (" Show the String"); bHandler = new ButtonHandler(); layout = new FlowLayout(); showTheString.addActionListener(bHandler); setLayout(layout); add(sampleString); add(showTheString); } class ButtonHandler implements ActionListener { public void actionPerformed(ActionEvent e) { samplestring.setText("Good Morning"); } } } Note: The methods need not be indicated on the diagram.


What is the java project architecture?


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


Can we call virtual funciton in a constructor ?


How to solve the problem of generating the unique hash keys with hash function?


when to use ArrayList and when to use HashMap in webApplication.


we have syntax like for(int var : arrayName) this syntax is to find whether a number is in the array or not.but i want to know how to find that number's location.


How to print nodes of a Binary tree?