Class-loader runtime diagnostic data

You can use the command-line parameter -Dibm.cl.verbose=<class_expression> to enable you to trace the way the class loaders find and load application classes.

<class_expression> can be any Java™ regular expression. For example, Dic* matches all classes with names begins with Dic.

Here is an example of using the -Dibm.cl.verbose parameter:

C:\j9test>java -Dibm.cl.verbose=*HelloWorld -mp . -m hw.HelloWorld

This example produces output that is similar to this:

ExtClassLoader attempting to find hw.HelloWorld
ExtClassLoader using classpath C:\sdk\jre\lib\ext\CmpCrmf.jar;C:\sdk\jre\lib\ext\dtfj-interface.jar;
C:\sdk\jre\lib\ext\dtfj.jar;C:\sdk\jre\lib\ext\gskikm.jar;C:\sdk\jre\lib\ext\ibmcmsprovider.jar;C:\s
dk\jre\lib\ext\ibmjcefips.jar;C:\sdk\jre\lib\ext\ibmjceprovider.jar;C:\sdk\jre\lib\ext\ibmkeycert.ja
r;C:\sdk\jre\lib\ext\IBMKeyManagementServer.jar;C:\sdk\jre\lib\ext\ibmpkcs11.jar;C:\sdk\jre\lib\ext\
ibmpkcs11impl.jar;C:\sdk\jre\lib\ext\ibmsaslprovider.jar;C:\sdk\jre\lib\ext\indicim.jar;C:\sdk\jre\l
ib\ext\jaccess.jar;C:\sdk\jre\lib\ext\JawBridge.jar;C:\sdk\jre\lib\ext\jdmpview.jar
ExtClassLoader path element C:\sdk\jre\lib\ext\CmpCrmf.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\dtfj-interface.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\dtfj.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\gskikm.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmcmsprovider.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmjcefips.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmjceprovider.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmkeycert.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\IBMKeyManagementServer.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmpkcs11.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmpkcs11impl.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\ibmsaslprovider.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\indicim.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\jaccess.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\JawBridge.jar does not exist
ExtClassLoader path element C:\sdk\jre\lib\ext\jdmpview.jar does not exist
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\CmpCrmf.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\dtfj-interface.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\dtfj.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\gskikm.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmcmsprovider.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmjcefips.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmjceprovider.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmkeycert.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\IBMKeyManagementServer.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmpkcs11.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmpkcs11impl.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\ibmsaslprovider.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\indicim.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\jaccess.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\JawBridge.jar
ExtClassLoader could not find hw/HelloWorld.class in C:\sdk\jre\lib\ext\jdmpview.jar
ExtClassLoader could not find hw.HelloWorld

AppClassLoader attempting to find hw.HelloWorld
AppClassLoader using classpath C:\j9test
AppClassLoader path element C:\j9test does not exist
AppClassLoader found hw/HelloWorld.class in C:\j9test
AppClassLoader found hw.HelloWorld

The sequence of the loaders' output is a result of the delegate first convention of class loaders. In this convention, each loader checks its cache and then delegates to its parent loader. Then, if the parent returns null, the loader checks the file system or equivalent. This part of the process is reported in the previous example.