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 49525

Differentiate Vector and ArrayList?

Wipro, Max Telecom,

6 5317

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


6 5769

What is an abstract class?


6 4740

How can final class be used?

Wipro, Accenture,

4 6657

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


1 7853

Java support what type of parameter passing ?


7 9097

Explain the term serialization?


10 7216

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


10 8386

What is Overriding and how can it be used?

Consagous, Wipro,

7 11399

Explain pass by reference and pass by value?

IBM, Wipro,

8 9241

In which way does a Primitive data type is passed ?

Sun Microsystems,

5 5685

What happens when a main method is declared as private?

L&T, DELL, Infosys, Sun Microsystems,

20 25938

Is there any need to import java.lang package?

Sun Microsystems,

13 12014

What is UNICODE?

3 3138

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Un-Answered Questions { Core Java }

what are the disadvantages of indexes in oracle?


What does those terms actually mean included in the j.d.k i.6?


how to deploy apache tomcat server to weblogic server in java


which pattern is default in scanner package?


Is there any way to find whether software installed in the system is registered by just providing the .exe file? I have tried the following code but its just displaying the directory structure in the registry. Here the code : package com.msi.intaller; import java.util.Iterator; import ca.beq.util.win32.registry.RegistryKey; import ca.beq.util.win32.registry.RootKey; public class RegistryFinder { public static void main(String... args) throws Exception { RegistryKey.initialize(RegistryFinder.class.getResource("jRe gistryKey.dll").getFile()); RegistryKey key = new RegistryKey(RootKey.HKLM, "Software\\ODBC"); for (Iterator subkeys = key.subkeys(); subkeys.hasNext();) { RegistryKey subkey =; System.out.println(subkey.getName()); // You need to check here if there's anything which matches "Mozilla FireFox". } } }


who can i handle multiple client in RMI


What is the difference between JDBC 1.0 and JDBC 2.0?


how to prepare for IT Officers Interview in Banks


How to Sort Strings which are given in List and display in ascending order without using java api.


What are the restrictions imposed by a Security Manager on Applets?.


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


How will you serialize a singleton class without violating singleton pattern?


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.


Howto get an object that will perform date & time calculations then format it for output in some different locales with different date style.can ne1 tel me the answer of this question.pls


Say you want to store the information about a number of pets in an array. Typical information that you could store for each pet (where relevant) would be • Breed of animal • Animal's name • Its birth date • Its sex • Whether it has been sterilised or not • When it is due for its next inoculation • When it last had its wings clipped For each type of pet (eg. dog, cat or bird) you would typically define a class to hold the relevant data. Note: You do not need to implement these classes. Just answer the following questions. 3.1.1 What would be the advantage of creating a superclass (eg. Pet) and declaring an array of Pet objects over simply using an array of Objects, storing each of the instances of the different pet classes (eg. Dog, Cat or Bird) in it? 3.1.2 Would you define Pet as a class or as an interface? Why? (2) (2)