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

Core Java Interview Questions

Questions Answers Views Company eMail

In the HashMap, we know the values but we dont know the key, then how can we get the key from HashMap ?????

Kanbay,

4 9197

What is Transient and volatile

iFlex,

10 33851

What is the differenc between Enemuration interface and iterator interface according to accessing?

4 8525

what is the difference between static block and static method

Huawei,

19 57922

What is Marker interface in java? and what is clone?

Persistent, Wipro,

16 36724

what is the difference between equals method and ==

IBM, Professional Access, TCS,

17 27944

how many design pattern r there? and wht design pattern u use and why ?

HP,

5 11187

what is the difference b/w PUT and POST method to send data to the server

Mind Tree,

5 14396

In the first round, there are 30 aptitude and 30 java questions. We are suppose to finish both the papers within 60 minutes. I cleared this round. Next was test for programming skills. In this section, Some 7 n's were asked. 1. What is the difference b/w sleep(1000) and wait(1000) 2. what is the diff b/w static block and static function? 3. Write a program to validate IP address using string tokenizer. 4. Write a program to create singleton class 5. write a function to reverse the string 6. Write a prog to print prime nos upto n. EX: If n=9, It shld print 1,2,3,5,7 7. One program on collections- Write a program to print no. of times a number is repeating in an array. EX- {1,3,1,2,5,7,3,7,34,3,8,3} It should print: 1- 2 times 3- 4 times and so on 7. Write a func to print fibonocci series After this I had technical interview, which went on for. 60 mins or so. There were qn's about multi threading, Exception handling and collection classes. Knowledge about collections was very important for the post I was interviewed for.

Huawei,

1 12239

how can i connect to database in a applet ?

1 4947

when to use abstract class and when to use interface?

Exterro, iGate, IonIdea,

16 58810

what is difference between class and object?

College School Exams Tests, HCL,

43 92203

when,where and how to use abstract class and interface

2 5695

explain oops concepts with examples?

AbhiBus, Beeline, DELL, HCL, Satyam, TCS, VLS, Wipro,

29 204749

how can u create the object with out new operator

2 9092

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Un-Answered Questions { Core Java }

Which java ide is used the most?

1022

How many bits is size_t?

1000

What is flush () in java?

1017

What is the default value of local and global variables?

1106

Can java arraylist hold different types?

1087

Explain about field hiding in java?

953

What is the difference between length and size in java?

1001

What is the definition of tree ?

1067

What is rule of accessibility in java?

1039

What is public/private protected in java?

1055

Is java util regex pattern thread safe?

1032

Explain the advantages of packages in java?

929

What is append in java?

1177

What is a local, member and a class variable?

1052

How do you escape in java?

1090

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