Probably you use the default installed java version, gnu classpath/gjc. We recommend the Sun JVM, but JVMs of other vendors should work as well
Search for "gjc" in the errormessages:
java.lang.ArrayIndexOutOfBoundsException at java.lang.System.arraycopy(libgcj.so.70) at java.io.ObjectInputStream.read(libgcj.so.70 ) at java.io.InputStream.skip(libgcj.so.70) at com.izforge.izpack.installer.Unpacker.run(Unpacker.java:425) at java.lang.Thread.run(libgcj.so.70)
or
12 Aug 2008 16:34:31,161 [P1-9] WARN (ServletHandler.java [handle]:629) - Error for /exist/logo.jpg java.lang.NoClassDefFoundError: org.apache.cocoon.reading.ImageReader at java.lang.Class.initializeClass(libgcj.so.81) at java.lang.Class.newInstance(libgcj.so.81)
or
Exception in thread "main" java.lang.InternalError: unexpected exception during linking: java.lang.ClassNotFoundException: javax.swing.JFrame at 0x004f8ca3: java.lang.Throwable.Throwable(java.lang.String) (/usr/lib/./libgcj.so.3) at 0x004ebb1e: java.lang.Error.Error(java.lang.String) (/usr/lib/./libgcj.so.3) at 0x004f9086: java.lang.VirtualMachineError.VirtualMachineError(java.lang.String) (/usr/lib/./libgcj.so.3)
ant can help you out to determine the java version:
ant -diagnostics | grep java.vm
or
build.sh diagnostics | grep java.vm
results in
java.vm.version : 1.5.0_13-119 java.vm.vendor : Apple Inc. java.vm.name : Java HotSpot(TM) Client VM java.vm.specification.name : Java Virtual Machine Specification java.vm.specification.vendor : Sun Microsystems Inc. java.vm.specification.version : 1.0 java.vm.info : mixed mode