Tested against solaris-amd64 on
SunOS vm-v20z-9 5.11 snv_146 i86pc i386 i86pc
Oracle Solaris 11 Express snv_146 X86

java -version
java version "1.6.0_22"
Java(TM) SE Runtime Environment (build 1.6.0_22-b02)
Java HotSpot(TM) Server VM (build 17.1-b03, mixed mode)

Test code attached.

To run test:
export JAVA_HOME=/net/.../6u23/promoted/latest/binaries/solaris-amd64
$JAVA_HOME/bin/javac TestRemoveAllSystem
$JAVA_HOME/bin/java TestRemoveAllSystem

Test failed with following exception:

Sep 2, 2010 7:09:16 AM java.util.prefs.FileSystemPreferences$3 run
WARNING: Could not create system preferences directory. System preferences are unusable.
Sep 2, 2010 7:09:18 AM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock System prefs.Unix error code -1209014447.
Exception thrown in clearNodes() of Nodes java.util.prefs.BackingStoreException: Couldn't get file lock.
Sep 2, 2010 7:09:19 AM java.util.prefs.FileSystemPreferences checkLockFile0ErrorCode
WARNING: Could not lock System prefs.Unix error code -1209010000.
Exception thrown = java.util.prefs.BackingStoreException: Couldn't get file lock.
RemoveAllSystemTest01() Fail
java.util.prefs.BackingStoreException: Couldn't get file lock.
        at java.util.prefs.FileSystemPreferences.sync(FileSystemPreferences.java:715)
        at java.util.prefs.FileSystemPreferences.flush(FileSystemPreferences.java:807)
        at TestRemoveAllSystem.RemoveAllSystemTest01(TestRemoveAllSystem.java:28)
        at TestRemoveAllSystem.main(TestRemoveAllSystem.java:9)