"The SableVM Project involves the development of a liberally-licensed free virtual machine for Java. SableVM has just made a preview release branch of SableVM that supports the JVMDI (Java Virtual Machine Debugging Interface) and JDWP (Java Debug Wire Protocol). These standard protocols are commonly used by tools like Eclipse (see the screen shots) to provide a rich and user-friendly system with visual debugging support.
"This release is an important breakthrough because SableVM is the first Open Source Java virtual machine that supports these protocols..."