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

Core Java Interview Questions

Questions Answers Views Company eMail

1.what is the exact difference between applet and frame? 2.Do we use main method in frames?

5 26202

diff between abstract methods and interfaces with programing (code) example?

2 5318

Is it compulsory to have atleast one abstract method in abstract class?

10 23505

public class Garbage { int a=0; public void add() { int c=10+20; System.out.println(c); System.out.println(a); } public static void main(String args[]) { Garbage obj=new Garbage(); System.gc(); System.out.println("Garbage Collected"); obj.add(); } } Above is a code in java used for garbage collection. object obj has been created for the class Garbage and system.gc method is called. Then using that object add method is called.System.gc method if called the obj should be garbage collected?

6 8025

Why cant we define System.out.println() inside a class directly?

5 11413

If all the methods in abstract class are declared as abstract then what is difference between abstract class and in interface?

Infosys, Synechron,

8 14727

why marker interfaces are there in java

Digital Group,

4 9392

How to validate the request (Eg:user name and password) in session(http session)? not in LDAP server ?

Saksoft,

1 5833

In C we use only compiler. Why java uses both compiler and interpreter? What is its significance?

5 17982

What are Advatages of Overloading and Overridding.

TCS, Wipro,

8 25479

Can we declare static variables in JSP page.

TCS,

3 23944

wHAT IS DEFAULT SPECIFIER IN JAVA wHAT IS DEFAULT CONSTRUCTOR IN JAVA wHAT IS DEFAULT METHOD IN JAVA

IBM,

12 19015

write java code to print second max number in the array

Huawei, IBAB,

12 23663

how to call One constructor from another;

Innodata Isogen,

10 17454

Write java code to print "Hello how are you" Thread1 should have "Hello" Thread2 should have "how are you" both the threads should start at the same time

Huawei,

4 9622

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Un-Answered Questions { Core Java }

What is character in data type?

929

How many bytes are a float?

945

what is the purpose of the wait(), notify(), and notifyall() methods? : Java thread

944

What is the purpose of assert keyword used in jdk1.4.x?

1027

What is the benefit of inner classes in java?

1052

Can we force the garbage collection to run?

911

what methods would you overwrite in java.lang.object class?

965

What is string intern in java?

986

What is the size of int?

1050

Differentiate between run time error and syntax error.

1079

What is the char data type?

953

Can a class be private or protected in java?

1016

What is difference between == and === in js?

974

How can you set an applet’s height and width as a percentage?

891

Why we do exception handling in java and how many types of exceptions are there?

1068

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