The spec for javax.tools.ToolProvider::getSystemToolClassLoader specifies to return null if no tool is provided. ToolProvider now finds javac and javadoc.

Currently, in jdk9, it always returns the application class loader unconditionally which is a bug.

On the other hand, what should it return if jdk.compiler or jdk.javadoc is present in the image but not both? spec clarification might be needed.