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

Core Java Interview Questions

Questions Answers Views Company eMail

my method "abc" return array of interface "xyz" and "pqr" is abstract class implements abc and class "jkl" extends pqr My problem 1) when i call abc it retrun array xyz how can i do this hint xyz refer_xyz = new jkl(); but i can't create array. 2)I want to access method of jkl using reference of xyz??

1 3914

why interaction with server using javascript is difficult

1 3853

StringBuilder s = new StringBuilder("Hello Mom");s.append(",I mean,Mother"); Response.Write(s.ToString()); String s = "Hello Mom"; s+ = ",I mean Mom"; Response.Write(s); Which is faster ? which uses the most memory?

HCL,

6 8972

I have one Shopping cart application, i that i have selected some items, while clicking submit button by mistake i have clicked twice or trice, that time items are selected twice or trice. Actually i want only one copy of items but its selected twice or trice. So how can we avoid this problem?

Honeywell,

2 6846

How Vector class is synchronized,How to build user defined class as synchronized?

2058

What is difference between abstract class & final class

7 27048

Hai all I want to print given array in reverse order Ex: int a[]={1,2,3,4,5};display this array in reverse order.

4 6087

what is the output ? Math.floor(-2.1) a)2 b)-2 c)-3.0 d)0

Accenture,

4 13896

How to find the size of an array a)array.length() b)array.length c)array.size() d)array.size

Accenture,

6 10971

what is the Yield() method used in threads?

Accenture,

4 8565

System.out.println(101/14) what is the output? a)6 b)14 c)7.14 d)0

Accenture,

8 10664

when a servlet sends request for first time it uses the follwing methods a)init b)doget() c)dopost() d)service

Accenture,

4 7510

What is Hash Code in Java?

Cognizant,

6 15993

What are uses of Hash Code?

Cognizant,

2 7461

I have 100 records in a table with two rows. I need to display 10 records per page like Google Search. I need only the Logic(Pagination) in Pure Java. No JSP and all..Thanks in Advance...

Cybernet,

2 8016

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Un-Answered Questions { Core Java }

Is heap stored in ram?

964

How do you convert boolean to boolean?

1158

Compare overloading and overriding?

1005

Why hashmap is used in java?

1093

how come we know the object is no more used in the class?

6465

What are heap memory and stack memory and what are memory tables.

989

How can I become a good programmer?

983

Can you call a method in a method?

1093

Explain the difference between call by refrence and call by value?

1022

How do you implement tree mirroring in java?

1077

How many types of design patterns are there?

1102

What is abstract class? Explain

1044

What is a parameter in matrices?

1051

What does escaping a character mean?

1017

What is Java Annotations?

1103

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