Core Java Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

Core Java Interview Questions

Questions Answers Views Company eMail

The following program is Overloading or Overriding? public class PolymorphismEx { public int sampleMethod(int a) { return a; } public String sampleMethod(int a) { return "Is it Overloading or Overriding???"; } }

Ness Technologies, TCS,

4 7601

I Have a class abstract with one abstract method, so that method should override in the subclass, but i dont want to override, if i am not override what will happen? If compilation will occur then i dont want to give compilation error, then what we need to do??? See the sample program. public abstract class AbstractExample { public abstract void sampleMethod(); } public class AbstractExampleImple extends AbstractExample { }

Mphasis,

2 6031

is it mandatory to deaclare all variables public static fianl in interfaces?if i declare like in the below program, public interface A { public static final int I=0; int j=0; } in interface A,what is the difference between I,j?

2 4546

public class Test { public static void main(String[] args) { int countA = 0; int countB = 0; int countC = 0; int countD = 0; int countE = 0; int countF = 0; int countG = 0; int countH = 0; int countI = 0; int countJ = 0; int countK = 0; int countL = 0; int countM = 0; int countN = 0; int countO = 0; int countP = 0; int countQ = 0; int countR = 0; int countS = 0; int countT = 0; int countU = 0; int countV = 0; int countW = 0; int countX = 0; int countY = 0; int countZ = 0; } } Can anybody tell me any alternate solution(like loop or something) to automate this initialization process. Ex:- for(char chr='A';chr<='Z'; chr++) { (int) String "count"+chr = 0; }

2335

what is different between static and non static methods ,using example

2 4192

Which collection object is faster to retrieving the data and inserting the data into it.

Jamcracker, Virtusa,

2 8450

what is the difference b/w static and final methods?

1 5118

what is data binding? give the example

TCS,

1 4833

what is deadlock in threads? with example

CTS, XOXO,

2 5611

Difference between abtsract & final

Nous,

1 4048

Difference between error and exception

Nous, TCS,

3 6048

Superclass of exception

Nous,

4 6651

Write POJO class as a key to hashmap???

2 12982

WAP to illustrate the use of interface

2 4178

Difference between Map & Hashmap

Mastek,

2 6507

Post New Core Java Questions

Un-Answered Questions { Core Java }

How do you define a method?

975

What is final class?

1019

What is exception in java?

1080

Can inner class extend any class?

1052

What is complexity and its types?

1028

Explain different types of wrapper classes in java?

1021

What is use of set in java?

994

What happens to the Exception object after handling an exception?

2367

How many bits are used to represent unicode, ascii, utf-16, and utf-8 characters?

1095

How do you clear a method in java?

1004

What is java util collection?

1080

Can we sort hashmap in java?

953

Can a class extends itself in java?

1019

How transient variable is different from volatile variable?

1074

explain local datetime api in java8?

1008

For More Un-Answered { Core Java } Questions Click Here