RFR: 8160950 Agent JAR added to app class loader rather than system class loader when running with -Djava.system.class.loader

[Mandy Chung]

> On Sep 7, 2016, at 12:27 PM, serguei.spitsyn at oracle.com wrote:
> 
> Webrev:
>   http://cr.openjdk.java.net/~sspitsyn/webrevs/2016/jdk/8160950-JLI-WLS.jdk2/


CustomLoader.java
  62             File f   = new File(System.getProperty("test.classes", "."), "Agent.class”);

CustomLoader should load Agent.class from Agent.jar that was added after appendToClassPathForInstrumentation is called.

Agent.java
  43     public static void
  44     premain(String agentArgs, Instrumentation instrumentation) {

Nit: maybe merge two lines and rename “instrumentation” variable to inst, if you want to shorten the line.

The test needs @modules java.instrument; otherwise the test will fail when running in a minimal image without java.instrument module.

I like David’s suggestion on the simplified error message:
   "Unable to add %s to system class path\n”

Mandy