PATH, JAVA_HOME and JRE_HOME best practices

Java applications usually start by batch files or shell scripts which among other things set the executable java from the JRE_HOME or JAVA_HOME or the PATH environment variables. What are the best practices in writing such scripts and setting the PATH and JRE_HOME and JAVA_HOME considering the following factors:

-security
-convenience for average end users
-multiple versions of JRE/JDK in the same machine

Should we find 'java' from the PATH, JRE_HOME or JAVA_HOME?

Is there any good online resources about these?

Thanks for your comments.

Jim

Jim,

Good question. We usually use JAVA_HOME.

More important than what you pick is that you document it in an easy way for your users to find out and know what to set if they haven't already!

JAVA_HOME should be set to the home folder of your JDK - typically C:\jdk1.6.0_05 (or whatever version and wherever you installed it).

JRE_HOME is hardly ever needed - I've never ever set it before.

PATH should include "%JAVA_HOME%\bin" for Windows or $JAVA_HOME/bin for Linux / Unix / ...
Depending on whether or not JAVA_HOME contains any spaces you'd want to put the entire path, including the \bin, in quotes.