Using JRE/JDK 1.4 and JRun 3
This mini-article will tell you that although JRun 3.x can use the Sun Microsystems JRE/JDK 1.4 beta software, Macromedia JRun does not support this configuration until Sun Microsystems releases an official full version of that software. A nice legal waiver of official support of another company's beta software, and a link to the new Java beta.
Using JRE/JDK 1.4 and JRun 3