Summary

Special property jdk.boot.class.path.append needs to be initialized to NULL and JVMTI_GetSystemProperty() should return a status of JVMTI_ERROR_NOT_AVAILABLE if the property value is NULL.

Problem

Property jdk.boot.class.path.append is currently initialized to "" and JVMTI_GetSystemProperty() returns a status of JVMTI_ERROR_NONE and a property value of "".

Solution

Change the implementation of jdk.boot.class.path.append to initialize it to NULL. See https://github.com/openjdk/jdk/pull/6868.

Specification

https://openjdk.java.net/jeps/261 A related option, -Xbootclasspath/a, allows files and directories to be appended to the default bootstrap class path. This option, and the related API in the java.lang.instrument package, is sometimes used by instrumentation agents, so for compatibility it is still supported at run time. Its value, if specified, is reported via the JDK-specific system property jdk.boot.class.path.append. This option can be passed to the command-line launcher, java, and also to the JNI invocation API.

This documents that the intent was that if Xbootclasspath/a is not specified then its value can't be reported by reading property jdk.boot.class.path.append.

Also see discussion in: https://bugs.openjdk.java.net/browse/JDK-8224791