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

Core Java Interview Questions

Questions Answers Views Company eMail

How to count occurrences of each duplicate element in a list {a,b,d,c,a,b} ? Thanks in Advance

TCS,

2 8355

What is meant by wrapper classes?

3 9097

how to get the max salary and name of employee from arraylist without using the Comperator or even Comparable interface?

2 27448

how can i take the inputs from users in java program?

Wipro,

7 11442

HOW TO PRINT A NO IN WORDS USING WHILE LOOP THE NO WILL BE PRINTED WHEN IT WILL BE IN THE RANGE BETWEEN 1 AND 3?

1 3818

hoe can u call a constructor of a private classs to other inherited claa??

1 3851

how can be object class inherited to all class in a program when java does not support multiple inheritance??

4 6364

can two class in a code be public??if yes then how??

2 4890

take an array with -ve and +ve value both.find out the nearest value of 0(zero).if two values are same like(-2 and +2)then extract +2 is nearest of 0(zero).

1983

Is there memory leaks in java?

3 5902

Need to use public,static keywords in main function?

5 7262

How core java/j2ee project performance can be measured ?

1 3853

If there are two notepad opened and working on it . is this a process or thread? computer based Live Example to differentiate between Thread , Process , and Multi tasking ?

TCS, Wipro,

3 7631

How Marker Interfaces are instruct to complete the desired need ?

2 4223

Matrix multiplication only using OOP concepts .

3932

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Un-Answered Questions { Core Java }

What is linked hashset and its features?

1064

Why main method is static in java?

1186

When will we use them?

1057

how a programmer confirms that the data submitted has been succesfully inserted into the database(either oracle or my sql).. How a programmer confirm if there is any problem with the program he wrote for insertion... ANS:--- >executeupdate method is having boolean return type, if anything goes wrong in data insertion or data updation, it would return false. otherwise, if it successfully inserts data into the database, it would return true NOW HOW TO I CHECK IN MY DURING EXECUTION WHETHER IT RETURNS TRUE OR FALSE... WELL IT WILL DISPLAY ANY MESSAGE OR NOT

2433

What is comparator in java?

1004

Can we use this () and super () in a method?

980

What is the use of a copy constructor?

992

Is java still necessary?

1084

How many types of voids are there?

993

How do you know if a value is nan?

1059

What is a numeric literal?

1085

I want to re-reach and use an object once it has been garbage collected. How it's possible?

1030

What is Recursion Function?

1208

FOR EXAMPLE WE R HAVING TWO LIST ELEMENTS ..BOTH LISTS CONTAINS ID,NAME,PLACE ..I NEED TO COMPARE BOTH IDS IN TWO LISTS,IF ID'S R SAME MEANS WE HAVE ADD THE DETAILS(LIKE NAME,PLACE) TO MAP...HOW IS POSSIBLE ?CAN ANY ONE SUGGEST?

3476

How to restrict a member of a class from inheriting by its sub classes?

1354

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