A variant of this was reported by the ZeroTurnaround folks on jigsaw-dev.

The system property jdk.boot.class.path.append can be set/changed by:

1. -Xbootclasspath/a
2. An agent changing the value of the property in Agent_OnLoad
3. AddToBootstrapClassLoaderSearch

If we have all three, in this sequence, then the AddToBootstrapClassLoaderSearch property value set in #2 will be replaced. This needs to be investigated as there is potential corruption going on too, at least this is what has been suggested on the jigsaw-dev list.

The attached agent is one test case to demonstrate things, consider this:

java -Xbootclasspath/a:boot -agentlib:agent Test

The value printed should be boot:mydir:foo.jar but it actually prints boot:foo.jar.

Now change agent.c to comment out the usage of AddToBootstrapClassLoaderSearch, the test will correctly print boot:mydir.