How many threads can a Java VM support? Does this vary by vendor? by operating system? other factors?
After playing around with Charlie's DieLikeACode class, it looks like the Java thread stack size is a huge part of how many threads you can create.
-Xss set java thread stack size
For example
java -Xss100k DieLikeADog
But, Java has the Executor interface. I would use that, you will be able to submit thousands of Runnable tasks, and have the Executor process those tasks with a fixed number of threads.