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

Core Java Interview Questions

Questions Answers Views Company eMail

Which is the best way to use for String concatenation in Java?

HCL,

7 22564

In Serialization, whether you will use Static variables?

HCL,

3 9887

How do you relate a Interface to a Class? Tell me in Detail?

4 8263

Is java supports multiple inheritance? explain?

BUET, Inforica,

12 20891

which swing component is similar to rich text box in .net/vb

1 5331

Which One is optimal to choose ? Syncronized hash map or Hash table with single thread model? How can a hash map syncronized with out using syncrozed blocks in programm?

Four soft,

3 9233

int a=10,b=20,c=30 a= b+c;b=a+c;c=a+b; System.out.println("The value is"+a+b+c;

Honeywell,

17 31551

int a=1; float b=1.0; System.out.println(a==b);

CTS, Honeywell, McAfee,

13 30399

what is difference between abstraction and interface?

FIC,

8 13368

waht happens when a return type ,even void is specified for a constructor?

11 35137

Describe inheritance as applied to java?

4 11668

what is a package?

11 15757

what is a thread?

IBM, SunGard,

13 22095

class{ ... ... interface myinterface{ ... ... } abstract class{ .. .. } ... .. .. } is this possible to write "Interface and/ or Abstract class inside a class ? if possible whcich one is possible is only interface? is only abstract?

Logica CMG,

2 8342

class A{ m2(){ } } class B extends A{ m2(){ } } class c extends B{ m2(){ } } class my_class extends c{ m2(){ } pulic static void main(){ ...My_class a = new my_class(); super.super.super.m2(); is this is leagal if not find what is the legal procedure in order to call A's version of m2(); }

Logica CMG,

8 20793

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Un-Answered Questions { Core Java }

What is private static class in java?

1020

Explain covariant method overriding in java.

1108

When do we use hashset over treeset?

1064

Explain purpose of sleep() method in java?

1123

What is java util hashmap?

989

What are alternatives to java serialization?

1128

Can we execute a program without main?

1028

Explain the difference between throw and throws in java?

1006

Can a method be overloaded based on different return type but same argument type?

970

What is jpa specification?

989

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

5665

Write an algorithm program in java for the following question.. In a VLSI design techniques,they used rectangles to design circuits. EVery rectangle is to be placed according to x,y coordinates. Check whether or not two rectangles overlap each other. Here overlapping of rectangles is acceptable, if 1) one rectangle intersect with other. 2) one rectangle fully covers other. The time of algorithm should not exceed o(n logn).

2731

What is a stringbuilder?

920

Does treeset use compareto?

978

What is thread pool in java with example?

1008

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