Multithreading in Java Programming Examples: Java threads provide a vital performance boost to nearly all apps. Discover how these threads are becoming a standard part of Java programming by exploiting Hyper-Threading Technology and the new multi-core Intel processors.

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Multi-Threading in a Java* Environment

By Allan McNaughton

Java* threads provide a vital performance boost to nearly all apps. Discover how these threads are becoming a standard part of Java* programming by exploiting Hyper-Threading Technology and the new multi-core Intel® processors.

Building programs around threads of execution — that is, around specific sequences of instructions — delivers significant performance benefits. Consider, for example, a program that reads large amounts of data from disk and processes that data before writing it to the screen (such as a DVD player). On a traditional, single-threaded program (the kind most client programs use today), where only one task executes at a time, each of these activities happens as a part of a sequence of distinct phases. No data is processed until a chunk of a defined size has been read. So the program logic that could be processing the data is not executed until disk reads are complete. This leads to inferior performance.

On a threaded program, one thread can be assigned to read data, another thread to process it, and a third to write it out to the graphics card. These three threads can operate in parallel so that data is being processed while disk reads are going on. And overall performance improves. Many other examples can be devised in which the ability to do two things at once will provide better performance. The Java virtual machine* (JVM*) is itself heavily threaded for just this reason.