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 8991

What is Transient and volatile

iFlex,

10 33506

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

4 8328

what is the difference between static block and static method

Huawei,

19 57303

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

Persistent, Wipro,

16 36210

what is the difference between equals method and ==

IBM, Professional Access, TCS,

17 27365

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

HP,

5 11016

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

Mind Tree,

5 14149

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 12178

how can i connect to database in a applet ?

1 4886

when to use abstract class and when to use interface?

Exterro, iGate, IonIdea,

16 58346

what is difference between class and object?

College School Exams Tests, HCL,

43 90879

when,where and how to use abstract class and interface

2 5585

explain oops concepts with examples?

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

29 203883

how can u create the object with out new operator

2 8986

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Un-Answered Questions { Core Java }

Is boolean a wrapper class in java?

1020

What is the difference between access specifiers and access modifiers in java?

1119

What package is math in java?

959

Implementations of set interface?

974

How to change value in arraylist java?

1120

Is java same as core java?

1054

what is the role of xml in core java?? and how we can use it?? can somebody give a sample program with explanation and from where i can read more about xml?????

2218

Is java an open source?

938

What is a heavyweight component?

996

What is boolean in java?

931

What are the important features of Java 10 release?

967

Why do we need singleton?

943

What is java util hashmap?

957

What is the range of the short type?

959

What is field name?

966

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