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,

1164

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

Amazon,

1035

Convert Binary tree to linked list.

Amazon,

1147

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

Amazon,

1158

worst case complexities of Quick sort and Merge sort.

Amazon,

1090

What do you mean by hashing?

Amazon,

1169

What is the definition of tree ?

Amazon,

1132

When can you say a graph to be a tree?

Amazon,

1138

What do you mean by constant time complexity?

Amazon,

1350

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

Amazon,

1154

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

Amazon,

1153

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

Amazon,

1425

What are the differences between graph and tree?

Amazon,

1162

Differentiate between overriding and overloading cases?

Amdocs,

1176

Differentiate between run time error and syntax error.

Amdocs,

1200

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Un-Answered Questions { Core Java }

What is a list in java?

998

What are the elements of java?

1072

Why is the main method static?

1218

Add a value x to array from index l to r where 0 <= l <= r <= n-1

1138

What is a priority queue java?

1036

What are the important features of Java 11 release?

1166

Why can we not override static method?

1151

Explain about procedural programming language or structured programming language and its features?

1175

What is jit compiler ?

1042

Java.util.regex consists of which classes?

1048

How many inner classes can a class have?

1094

What about main thread in java?

1173

What is method in java with example?

1004

What is final method in java?

1088

What is a string what operation can be performed out with the help of a string?

1115

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