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,

31 47046

Differentiate Vector and ArrayList?

Wipro, Max Telecom,

4 4546

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

Wipro,

6 5043

What is an abstract class?

Wipro,

6 4037

How can final class be used?

Wipro, Accenture,

3 5889

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

Wipro,

1 7140

Java support what type of parameter passing ?

Wipro,

7 8275

Explain the term serialization?

Wipro,

10 6480

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

Wipro,

10 7678

What is Overriding and how can it be used?

Consagous, Wipro,

7 10750

Explain pass by reference and pass by value?

IBM, Wipro,

7 8651

In which way does a Primitive data type is passed ?

Sun Microsystems,

5 5006

What happens when a main method is declared as private?

L&T, DELL, Infosys, Sun Microsystems,

18 22514

Is there any need to import java.lang package?

Sun Microsystems,

13 11112

What is UNICODE?

3 2788


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Un-Answered Questions { Core Java }

What is inner class?what is the use of inner class?where we create the object for inner class? and inner class can extend any class or inner class can implement any interface?

618


what r advatages of websphere? & how to deploy?

612


Explain all java features with real time examples

98


In a container there are 5 components. I want to display all the component names, how will you do that?

573


4.1 Supply contracts (in the form of comments specifying pre- and post conditions) for the enqueue() method of the LinkedQueue class given in the Appendix. (2) 4.2 Let Thing be a class which is capable of cloning objects, and consider the code fragment: Thing thing1 = new Thing(); //(1) Thing thing2 = thing1; //(2) Thing thing3 = (Thing) thing1.clone(); //(3) Explain how the objects thing2 and thing3 differ from each other after execution of the statements. (

414


how to know the total memory occupied by the objects in the ArrayList(Array list may contain duplicate objects)

524


what are the disadvantages of indexes in oracle?

766


what type of questions asked for barclays technologies pune please send urgent

3659


What is files manifesting?

650


How to provide security in java

742


why using interface interface ?

462


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.

640


What are advantages of using Java?s layout managers than windowing systems?

888


FOR EXAMPLE WE R HAVING TWO LIST ELEMENTS ..BOTH LISTS CONTAINS ID,NAME,PLACE ..I NEED TO COMPARE BOTH IDS IN TWO LISTS,IF ID'S R SAME MEANS WE HAVE ADD THE DETAILS(LIKE NAME,PLACE) TO MAP...HOW IS POSSIBLE ?CAN ANY ONE SUGGEST?

1287


Q1.A. Write note on “The class path Environment Variable”? B. Which are different kinds of source code? Q2.A. How to create an interface? B. Why convert an applet to an application? Q3.A. How to use Media tracker Class. B. How to use string tokenizer class. Q4 A. Explain the overview of UDP messaging. B. Difference between SQL Exception class and SQL Warning class. Q5. A. How to create com object in Java? B. Write short notes on “The properties class” Q6. A. When object is created and destroyed? B. Explain the JDB in depth & command line. C. Write short notes on Web Sites.

4850