Java NIO for Not Yet Techies

Java NIO was added to the language with the release of Java 2 Standard Edition / J2SE 1.4. Once code-named Merlin, Java NIO stands for New Input Output. It contains new APIs that turn Java into a high performance language.

The input and output of data are critical points that determine the efficiency of a program or language. I recall my computer science teacher in college a million years ago telling us that the slowest parts of a computer process were the users, because -- being human beings -- we could not input or output data anywhere near as fast as the computer could process it. Java NIO goes a long way toward removing those barriers from that language.

Until the release of Java NIO, the Java Virtual Machine could not take advantage of the full potential of the underlying operating systems, because it was written to be universal. This slowed down input and output operations, especially for enterprise-large applications which worked with huge quantities of data.

It is contained in the java.nio package and subpackages. It now enables:

• File locking
• Non-blocking input/output
• Readiness selection
• Memory mapping

Java NIO is the first addition to Java that originated with the JCP / Java Community Process. It came from Java Specification Request #51. It also regular expression processing, such as Perl uses, to allow:

• Pattern matching
• Search and replace
• Look-ahead assertions
• Capture groups

Java NIO also enables character set coding, a charset API for complete control of character set coding and encoding. It contains new buffer classes which link its regular Java classes to channels. A channel is an object that models a communication connection -- which can be unidirectional or bidirectional.

Java NIO also contains socket channels for network interaction. The selector class does readiness selection.

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