For Windows platform :
Base team has modified the windows platform support warning messages since the messages were too strong. L10N should retranslate the messages (see bugid 4799113) and the message was "This Java(TM) Platform does not support the operating system on this machine. The operating systems that this Java(TM) Platform supports are:\n\n Windows NT 4.0 with Service Pack 5 or later\nWindows 2000 with Service Pack 2 or later\nWindows 98\nWindows ME\nWindows XP\n\n ".
This bug will be fixed in Mantis-beta or later version.