I've been corresponding with Andy Higgins a bit about the Sametime Awareness Simulator (SAS) I wrote some years back and which is still getting surprisingly many downloads. SAS is written in Java and Andy was unable to make it run on his Oracle JVM but after debugging a bit I found out that a 32 bit JVM was required. Unfortunately Andy was still unable to make it work so he turned to wiser people than me and contacted Carl Tyler who helped him. Apparently there was an issue with the class format so to make it work he had to use an older JVM. I was able to make it work with a 32 bit version of Java 5 and Andy used the JVM supplied with the Notes client.
As SAS is written using the Eclipse runtime Carl could supply a command line to start SAS using an alternate JVM:
sas -clean -vm <path to JVM>Andy used
sas -clean -vm N:\notes\jvm\bin\java(where n:\notes is your notes program directory)
Hope it helps.