A number of serviceability fail intermittently with NoClassDefFoundError when run with jtreg and concurrency. The following is an incomplete list of the tests that are impacted:

    com/sun/tools/attach/ProviderTest.java
    java/lang/instrument/DaemonThread/TestDaemonThread.java:
    java/lang/instrument/PremainClass/PremainClassTest.java
    java/lang/instrument/PremainClass/ZeroArgPremainAgentTest.java
    sun/tools/jstatd/TestJstatdDefaults.java:
    sun/tools/jstatd/TestJstatdExternalRegistry.java:
    sun/tools/jstatd/TestJstatdPort.java:
    sun/tools/jstatd/TestJstatdPortAndServer.java:
    sun/tools/jstatd/TestJstatdServer.java:
    sun/tools/jstatd/TestJstatdUsage.java:
    com/sun/tools/attach/BasicTests.java:
    com/sun/management/HotSpotDiagnosticMXBean/CheckOrigin.java

A typical failure is:

java.lang.NoClassDefFoundError: jdk/testlibrary/JDKToolFinder
at jdk.testlibrary.ProcessTools.createJavaProcessBuilder(ProcessTools.java:275)
at jdk.testlibrary.ProcessTools.executeTestJvm(ProcessTools.java:314)
at ProviderTest.runTests(ProviderTest.java:81)
at ProviderTest.main(ProviderTest.java:52)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:484)
at com.sun.javatest.regtest.MainAction$SameVMRunnable.run(MainAction.java:754)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassNotFoundException: jdk.testlibrary.JDKToolFinder
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
... 10 more
java.lang.NoClassDefFoundError: jdk/testlibrary/JDKToolFinder
at jdk.testlibrary.ProcessTools.createJavaProcessBuilder(ProcessTools.java:275)
at jdk.testlibrary.ProcessTools.executeTestJvm(ProcessTools.java:314)
at ProviderTest.runTests(ProviderTest.java:81)
at ProviderTest.main(ProviderTest.java:52)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:484)
at com.sun.javatest.regtest.MainAction$SameVMRunnable.run(MainAction.java:754)
at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ClassNotFoundException: jdk.testlibrary.JDKToolFinder
at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
at java.lang.ClassLoader.loadClass(ClassLoader.java:426)
at java.lang.ClassLoader.loadClass(ClassLoader.java:359)
... 10 more