Home arrow Java arrow Multithreading in Java
JAVA

Multithreading in Java


Multithreading allows two parts of the same program to run concurrently. This article discusses how to pull off this performance-improving feat in Java. It is excerpted from chapter 10 of the book Java Demystified, written by Jim Keogh (McGraw-Hill/Osborne, 2004; ISBN: 0072254548).

Author Info:
By: McGraw-Hill/Osborne
Rating: 4 stars4 stars4 stars4 stars4 stars / 535
August 04, 2005
TABLE OF CONTENTS:
  1. · Multithreading in Java
  2. · Overhead
  3. · The Thread Classes and the Runnable Interface
  4. · Creating Your Own Thread
  5. · Creating a Thread by Using extends
  6. · Using isAlive() and join()
  7. · Setting Thread Priorities
  8. · Synchronizing Threads
  9. · Using the Synchronized Statement
  10. · Suspending and Resuming Threads

print this article
SEARCH DEVARTICLES

Multithreading in Java
(Page 1 of 10 )

Marathon runners sometimes are faced with a dilemma when two major races fall during the same week because they have to choose which race to run in. They probably wish there was a way a part of them could go to one race and another part to the other race. That can’t happen—that is, unless the runner is a Java program, because two parts of the same Java program can run concurrently by using multithreading. You’ll learn about multithreading and how to run parts of your program concurrently in this chapter.

Multitasking

Multitasking is performing two or more tasks at the same time. Nearly all operating systems are capable of multitasking by using one of two multitasking techniques: process-based multitasking and thread-based multitasking.

Process-based multitasking is running two programs concurrently. Programmers refer to a program as a process. Therefore, you could say that process-based multitasking is program-based multitasking.

Thread-based multitasking is having a program perform two tasks at the same time. For example, a word processing program can check the spelling of words in a document while you write the document. This is thread-based multitasking.

A good way to remember the difference between process-based multitasking and thread-based multitasking is to think of process-based as working with multiple programs and thread-based as working with parts of one program.

The objective of multitasking is to utilize the idle time of the CPU. Think of the CPU as the engine of your car. Your engine keeps running regardless of whether the car is moving. Your objective is to keep your car moving as much as possible so you can get the most miles from a gallon of gas. An idling engine wastes gas.

The same concept applies to the CPU in your computer. You want your CPU cycles to be processing instructions and data rather than waiting for something to process. A CPU cycle is somewhat similar to your engine running.

It may be hard to believe, but the CPU idles more than it processes in many desktop computers. Let’s say that you are using a word processor to write a document. For the most part, the CPU is idle until you enter a character from the keyboard or move the mouse. Multitasking is designed to use the fraction of a second between strokes to process instructions from either another program or from a different part of the same program.

Making efficient use of the CPU may not be too critical for applications running on a desktop computer because most of us rarely need to run concurrent programs or run parts of the same program at the same time. However, programs that run in a networked environment, such as those that process transactions from many computers, need to make a CPU’s idle time productive.


blog comments powered by Disqus
JAVA ARTICLES

- Java Too Insecure, Says Microsoft Researcher
- Google Beats Oracle in Java Ruling
- Deploying Multiple Java Applets as One
- Deploying Java Applets
- Understanding Deployment Frameworks
- Database Programming in Java Using JDBC
- Extension Interfaces and SAX
- Entities, Handlers and SAX
- Advanced SAX
- Conversions and Java Print Streams
- Formatters and Java Print Streams
- Java Print Streams
- Wildcards, Arrays, and Generics in Java
- Wildcards and Generic Methods in Java
- Finishing the Project: Java Web Development ...

Watch our Tech Videos 
Dev Articles Forums 
 RSS  Articles
 RSS  Forums
 RSS  All Feeds
Write For Us 
Weekly Newsletter
 
Developer Updates  
Free Website Content 
Contact Us 
Site Map 
Privacy Policy 
Support 

Developer Shed Affiliates

 




© 2003-2014 by Developer Shed. All rights reserved. DS Cluster - Follow our Sitemap
Popular Web Development Topics
All Web Development Tutorials