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PLEASE NOTE, THIS IS VERY OLD ARCHIVE INFORMATION AND MAY NOT FUNCTION ON NEW SERVERS

Java

Java is a programming language created by Sun Microsystems that offers many benefits to professional programmers and application developers. Java is a byte-compiled language and is completely portable. You can execute the same Java code (or Java class) on a wide range of operating system platforms. Java is much faster than interpreted languages (TCL, Perl, et al), but cannot run as fast as fully compiled languages (C, C++).

Because of its portability, Java and the World Wide Web make an excellent match. Web designers can embed Java applets into their web content for display in Java-enabled browsers like Netscape Navigator and Microsoft Internet Explorer. The applets are downloaded over the Internet within the context of the web document and are then executed on the local computer. Applets can add interactivity, animation, multimedia, or a database interface to an otherwise dull and listless web site.

The Java Virtual Machine is at the heart of the Java programming language. It is the engine that actually executes Java code. You can't run a Java class or Java applet without also running an implementation of the Java Virtual Machine. When Java code is executed, the instructions are not executed directly by the hardware of the local system. Instead the Java Virtual Machine walks through the instructions step by step and carries out the action the instruction represents. This provides a level of protection between your computer and the software you run on your computer.

Using Java on Your Virtual Server

There are several Java tools which are currently available on your Virtual Server. The tools are compatible with version 1.0.2 of the Java spec. The 1.0.2 spec is supported by all Java enabled browsers.

  • javac - Java Bytecode Compiler
    javac compiles Java source code (.java files) into .class files that contain the Java bytecode for the class. To compile an example file called Test.java, do something like this: 

    % javac Test.java

    The resulting .class file can then be embedded into web content.

  • java - Java Virtual Machine (Interpreter) and "Just-In-Time" Compiler
    The Java Virtual Machine is an interpreter for Java bytecode. To execute the sample Test.class bytecode compiled using the javac command above, do something like this: 

    % java Test

    The Java Virtual Machine installed on the servers running FreeBSD is java_X 1.18.

    The Java Virtual Machine installed on the servers running BSD/OS is Kaffe 0.84. Kaffe version 0.91 (which is Java 1.1 compliant) is available as well. The Java version 1.1 compliant interpreter can be executed using the java1.1 command.

    NOTE: If your Virtual Server was ordered after Nov 22, 1999, you are likely running FreeBSD. To find out which O/S your Virtual Server is running, use the uname command: 

    % uname

    If your Virtual Server is not already running FreeBSD, Upgrade to a New FreeBSD Virtual Server today!

    These Java Virtual Machines also include a "Just-in-time" (JIT) code generator. JIT is a technique for speeding up the execution of interpreted programs. Just before a method is run for the first time, the machine-independent Java bytecode for the method is converted into native machine code. This native machine code can then be executed by the computer directly, rather than via interpreter. JIT code generator greatly increases the speed of interpreted bytecode to nearly the speed of compiled code.

PLEASE NOTE, THIS IS OLD ARCHIVE INFORMATION AND MAY NOT FUNCTION ON NEW SERVERS