These tests worked fine with jtreg 4.1, but it looks like we need to explicitly specify the classpath for NoJavaLang.java (compiled by CheckExamples) and NoJavaLangTest.java when run with jtreg 4.2 and later.

Here is an example of running CheckExamples.java
===
----------System.err:(29/1937)----------
Error: Example /home/dbuck/check_langtools/test/tools/javac/diags/examples/NoJavaLang.java declares key compiler.misc.fatal.err.no.java.lang but does not generate it
Error: Example /home/dbuck/check_langtools/test/tools/javac/diags/examples/NoJavaLang.java generates key compiler.err.cant.access but does not declare it
Error: Example /home/dbuck/check_langtools/test/tools/javac/diags/examples/NoJavaLang.java generates key compiler.err.error but does not declare it
Error: Example /home/dbuck/check_langtools/test/tools/javac/diags/examples/NoJavaLang.java generates key compiler.misc.class.file.not.found but does not declare it
Error: Example /home/dbuck/check_langtools/test/tools/javac/diags/examples/NoJavaLang.java generates key compiler.misc.count.error but does not declare it
332 examples checked
115 keys on not-yet list

prefix #keys in tests #keys in javac %
compiler.err. 218 263 82%
compiler.warn. 60 74 81%
compiler.note. 17 17 100%
compiler.misc. 82 138 59%
other 0 0
total 377 492 76%
java.lang.Exception: 5 errors occurred.
        at CheckExamples.run(CheckExamples.java:124)
        at CheckExamples.main(CheckExamples.java:55)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at com.sun.javatest.regtest.agent.MainWrapper$MainThread.run(MainWrapper.java:127)
        at java.lang.Thread.run(Thread.java:745)
===

Since JPRT upgraded to jtreg 4.2 last year, langtools testing has been failing. These test was blacklisted for 8u-cpu, but 7u-cpu still fail CheckExamples.java OOTB. Both releases should be fixed. This was fixed in JDK 9 and later as part of JDK-8177530 [0].

[0] http://hg.openjdk.java.net/jdk9/jdk9/langtools/rev/4012b3f11f0d