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

Core Java Interview Questions

Questions Answers Views Company eMail

Implement a stack with push (), pop() and min() in O(1) time.

Amazon,

1112

Find the value of a specified element of the array arr[i] where 0 <= i <= n-1

Amazon,

982

Convert Binary tree to linked list.

Amazon,

1093

Convert a BST into a DLL and DLL to BST in place.

Amazon,

1116

worst case complexities of Quick sort and Merge sort.

Amazon,

1032

What do you mean by hashing?

Amazon,

1108

What is the definition of tree ?

Amazon,

1038

When can you say a graph to be a tree?

Amazon,

1083

What do you mean by constant time complexity?

Amazon,

1248

Write a program to show whether a graph is a tree or not using adjacency matrix.

Amazon,

1097

You're given a Boolean 2D matrix, can you find the number of islands?

Amazon,

1109

What steps are taken when the OS shifts from one-thread execution to another?

Amazon,

1366

What are the differences between graph and tree?

Amazon,

1122

Differentiate between overriding and overloading cases?

Amdocs,

1106

Differentiate between run time error and syntax error.

Amdocs,

1134

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Un-Answered Questions { Core Java }

What causes memory leaks in java?

936

Which method you will use to create a new file to store some log data. Each time a new log entry is necessary, write string to the file in java ?

1161

Can we write method inside a method in java?

989

What is the use of conditional statement?

985

What is api data?

1000

What is difference overloading and overriding?

1170

What is main in java?

1151

Explain the key functions of data binding?

1021

Is alive method in java?

981

What is an immutable object?

1100

Why java is secure? Explain.

1043

What are parameters in a method?

1106

What do you mean by platform independence?

1053

Does every java program need a main?

998

What is the difference between declaration and definition in java?

1076

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