# JavaTM Platform Debugger Architecture
Known Bugs and Limitations

- The debugged VM can crash when very large numbers of events are generated. This is especially noticeable if you enable all method entry and exit events for a large application.
- Some events that occur at the same location are not properly combined into event sets; instead, they are reported separately as single-element event sets. This happens when events of different kinds occur at the same thread and location.
- The setValue method sometimes fails with an incorrect ClassNotLoadedException when the destination Field, LocalVariable, or ArrayReference element has an array type.
- An attempt to use a StackFrame that is no longer valid (i.e. its thread has been resumed since it was retrieved), can result in a crash in the target VM.
- Generated parser files for JDB use deprecated APIs from the Java 2 Platform libraries.
- Synthetic fields and methods are not suppressed nor are they distinguished from non-synthetic members.
- In-process debugging through the JDI is not supported.
- Constructors have the name "<init>" and method style signatures, for example the default constructor has the signature "()V".

The following bugs exist in the current Win32 classic VM JVMDI implementation and in the Solaris Reference VM implementation. They will be fixed in the first maintenance release of the Java 2 SDK.

- For classes compiled without -g, JDI responds to queries for local variables with empty lists instead of throwing the appropriate AbsentInformationException.
- Some breakpoints at the start of methods are not reported if you are also stepping over the method invocation.
- Incorrect local variable values are reported during method exit events.
- Redundant step events are generated when instruction stepping through quicked instructions for the first time.

The current production release of the Sun SolarisTM VM cannot be used with this release. The Solaris Reference implementation can be used, however, with the limitations listed above.

Copyright © 1999 Sun Microsystems, Inc. All Rights Reserved. Please send comments to: java-debugger@java.sun.com |