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JSwat Project

How To: Run Classic VM


Do you have a Classic VM?

The first question to answer is, do you even have a Classic VM that you can run? If you are using Solaris JDK 1.3 or any of the 1.4 JDKs, you will only have the HotSpot VM. I believe this is a mistake on JavaSoft's part, since the Classic VM is much more stable and has fewer problems being debugged. Nonetheless, they control what we can do so there you are. If you have the Classic VM available to you, continue below.

Running the Classic VM

There are a couple of ways to run the Classic VM in place of the HotSpot VM. One is to modify the <JAVA_HOME>/jre/lib/jvm.cfg file, and the other is to pass -classic whenever you invoke JSwat and launch the debuggee VM. The former is easier to deal with, so let's look at that in more detail.

Typically the <JAVA_HOME>/jre/lib/jvm.cfg file has the "-hotspot" line before all the other lines. To use the Classic VM by default, simply edit this file and put the "-classic" line before all of the others. Then whenever you start a JVM, it will run with the Classic interpreter.



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