Running Spark on java 1.6.0 in Linux always gets the error:
Error: Couldn't find per display information
It is caused by a bug in jdic tray icon library. Latest version of jdic has solved this problem. https://jdic.dev.java.net/servlets/ProjectDocumentList?expandFolder=4183&folderID=5497
Notice that this problem did not happen in java 1.5. Some linux (as Fedora) have problems running spark with Java 1.5, after login, the windows is blank.