Running Different Softare Versions on Unix

In order to run a specific version of Java, you need to set the environment variable JAVA_HOME to the root directory of the version you'd like to run. All available versions, i.e.

• 1.4
• 1.3
• 1.2.0
• 1.1.7
• 1.1.6
• 1.1.5
• 1.1.4
• 1.1.3
• 1.1.1
• 1.1
• .0.1

So, if you're using csh or tcsh and wish to run Java 1.3, you would type:

Code listing 1.1

setenv JAVA_HOME /depot/J2SE-1.3

at your shell prompt, and for the Bourne shell or derivatives thereof, the command would be:

Code listing 1.2

export JAVA_HOME=/depot/J2SE-1.3

In addition, you need to verify that you are running the Java executables /usr/local/bin. If it turns out you're running them somewhere else, ensure that /usr/local/bin comes first in your PATH variable. You can modify this variable in your .cshrc file.

Here is some more info about currently installed versions and about Sun's software for compiling and debugging Java applications and applets. The following executables are available in the JDK:

Name of executable	Invocation command	Program description
Java Compiler	javac	Compiles programs written in the Java programming language into bytecodes.
Java Interpreter	java	Executes Java bytecodes. In other words, it runs programs written in the Java programming language.
Java Runtime Interpreter	jre	Similar to the Java Interpreter (java), but intended for end users who do not require all the development-related options available with the java tool.
Java AppletViewer	appletviewer	Used for testing and running applets.
Java Debugger	jdb	Helps you find bugs in Java programs.
Class File Disassembler	javap	Disassembles compiled Java files and prints out a representation of the Java bytecodes.
Java Documentation Generator	javadoc	Parses the declarations and documentation comments in a set of Java source files and produces a set of HTML pages describing the public and protected classes, interfaces, constructors, methods, and fields. Also produces a class hierarchy and an index of all members.
C Header and Stub File Generator	javah	For attaching native methods to Java code.
Java Archive Tool	jar	Combines many Java class files and other resources into a single jar file.
Digital Signing Tool	javakey	Manages entities, including their keys, certificates, and the trust associated with them.
Native-To-ASCII Converter	native2ascii	Converts a native encoding file to an ascii file that includes the \udddd Unicode notation.
Java RMI Stub Converter	rmic	Generates objects from the names of compiled Java classes that contain remote object implementations.
Java Remote Object Registry	rmiregistry	Creates and starts a remote object registry on the specified port of the current host.
Serial Version Command	serialver	Returns the serialVersionUID for one or more classes in a form suitable for copying into an evolving class.
AWT 1.1 Conversion Tool	updateAWT	Included with the JDK AWT documentation, rather than in the bin directory. Updates deprecated 1.0 AWT names to new 1.1 AWT names (for Sun Solaris and UNIX systems, or Windows systems with the MKS toolkit).
Various C libraries and include files

To run a specific version of Netscape, you need to set the environment variable NETSCAPE_VERSION to the version number you prefer. For instance, to run version 4.75, in the csh you would type

Code listing 2.1

setenv NETSCAPE_VERSION 4.75

at your shell prompt, and for the Bourne shell and its derivatives:

Code listing 2.2

export NETSCAPE_VERSION=4.75

You also need to ensure that the running the executables as /usr/local/bin/netscape. If you find you're running them somewhere else, you need to modify your PATH variable. You can this in your .cshrc file.