RFR(XL): 8157957 - ClassNotFoundException: jdk.test.lib.JDKToolFinder

Christian Tornqvist christian.tornqvist at oracle.com
Fri Aug 12 15:32:45 UTC 2016

Hi everyone,


Please review this fix for the CNFE issue we've had in the Hotspot jtreg
tests. The two big culprits for the intermittent CNFE are: Duplicate classes
on classpath with different content and @build tags causing class files to
be written in bad places.


There has been a lot of confusion around when there's a need to add @build
to a test. In general it turns out it has been overused, which can lead to
side effects. Here's an easy rule:


If you run only that test in a clean jtwork folder and it passes, then
there's no need for @build. 


If it doesn't pass, then it might need an explicit @build, here are some
examples when it might be needed:


* If the class is used by ClassFileInstaller and this is invoked by @run
main ClassFileInstaller (sun.hotspot.Whitebox is an example of this)

* If it's a class that that doesn't have reference from the Test itself (if
"javac Test" wouldn't compile it, you might need to explicitly @build it)


The change includes:


* Removing all unnecessary @build tags, some of the CNFE was due to use of
it to compile classes in /test/lib or /testlibrary when having different
classpath (@library) set.

* Changed @build <testname> to @build sun.hotspot.Whitebox

* Moved /test/lib/share/classes/jdk/test/lib to /test/lib/jdk/test/lib 

* Some of the classes in /hotspot/test/testlibrary was only used by one or
two tests, these classes shouldn't be part of the shared testlibrary code
and they were moved to the location of the test

* Merged/moved the classes in /hotspot/test/testlibrary to /test/lib

* Moved some of the /test/lib classes into packages

* Changed @library /testlibrary to @library /test/lib

* Changed imports from jdk.test.lib.* to explicit imports to help in future


Almost all of the changes in here are in the jtreg @build and @library tags,
very little code has been touched. Copyright headers will be updated before


Testing done: Ran the entire hotspot/test/ folder multiple times locally and
in RBT





A recently added test required me to fix that as well, generating and
uploading a new webrev of the Hotspot repo changes takes about 3h though, so
here's the diff for that file:


diff -r f37577c20a6b test/serviceability/sa/sadebugd/SADebugDTest.java

--- a/test/serviceability/sa/sadebugd/SADebugDTest.java Wed Aug 10 21:02:14
2016 -0400

+++ b/test/serviceability/sa/sadebugd/SADebugDTest.java Fri Aug 12 11:25:54
2016 -0400

@@ -26,7 +26,7 @@

  * @summary Checks that the jshdb debugd utility sucessfully starts

  *          and tries to attach to a running process

  * @modules java.base/jdk.internal.misc

- * @library /test/lib/share/classes

+ * @library /test/lib


  * @run main/othervm SADebugDTest










More information about the hotspot-dev mailing list