Most asked top Interview Questions and Answers | Online Test | Mock Test
Education platform for interview prep, online tests, tutorials, and live practice

Build skills with focused learning paths, mock tests, and interview-ready content.

WithoutBook brings subject-wise interview questions, online practice tests, tutorials, and comparison guides into one responsive learning workspace.

Search the library
Prepare Interview

Mock Exams

Make Homepage

Bookmark this page

Subscribe Email Address

Core Java Interview Questions and Answers

Question: What is concurrency in java?
Answer:

Concurrency is the ability to run several programs or several parts of a program in parallel. If a time consuming task can be performed asynchronously or in parallel, this improve the throughput and the interactivity of the program.

A modern computer has several CPU's or several cores within one CPU. The ability to leverage these multi-cores can be the key for a successful high-volume application.

Concurrency Issues:

Threads have their own call stack, but can also access shared data. Therefore you have two basic problems, visibility and access problems.

A visibility problem occurs if thread A reads shared data which is later changed by thread B and thread A is unaware of this change.

An access problem can occur if several thread access and change the same shared data at the same time.

Visibility and access problem can lead to

  • Liveness failure: The program does not react anymore due to problems in the concurrent access of data, e.g. deadlocks.

  • Safety failure: The program creates incorrect data.

Save For Revision

Bookmark this item, mark it difficult, or place it in a revision set.

Open My Learning Library
Is it helpful? Yes No

Most helpful rated by users:

©2026 WithoutBook