JDK-7079839 : IE 9 not find java 6 plugin after unintall JDK 7
  • Type: Bug
  • Component: deploy
  • Sub-Component: plugin
  • Affected Version: 6u29
  • Priority: P2
  • Status: Resolved
  • Resolution: Fixed
  • OS: windows_xp
  • CPU: x86
  • Submitted: 2011-08-16
  • Updated: 2011-11-21
  • Resolved: 2011-09-27
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7u2 b08Fixed 8Fixed
Related Reports
Relates :  
J2SE Version (please include all output from java -version flag):

Does this problem occur on J2SE 1.4.x, 1.5 or 6?  Yes / No (pick one)
  also with 6u26

Operating System Configuration Information (be specific):
  Windows 64-bit system 
  IE 9

Bug Description:

  installed the Java 7 Plug-in, both 32 and 64-bit, on 64-bit
Windows 7 system.  That works fine.

  When uninstall both 32 and 64-bit Java 7 Plug-Ins and install 
Java 6 Update 26 or 28 (the only 2 updates have tried), 
again both 32 and 64-bit variations, <applet> tags in 64-bit 
MSIE 9 don't find the Java 6 Plug-In.  
All is well once when move back to Java 7, though.

  The general oddity did block CAP member from testing with 64-bit 
MSIE and no bother testing 32-bit MSIE on my 64-bit system.

  It seems like an <applet> tag wide issue -- as if Java 6 wasn't 
re-registering with MSIE properly after Java 7 was installed.

  Had Java 6 working just fine in MSIE 9 with the same tags and
don't *think* anything else changed other than installing Java 7.

  Have a policy of having only 1 Java Plug-In version installed 
at a time as have seen too much weirdness over the years 
resulting from multiple Java Plug-In versions being installed 
even though that should work fine.

EVALUATION The problem is due to during uninstall of jre7, the following key wasn't removed: [HKEY_CLASSES_ROOT\CLSID\{08B0E5C0-4FCB-11CF-AAA5-00401C608501}\TreatAs] @="{CAFEEFAC-0017-0000-0000-ABCDEFFEDCBB}" On installing of 6 update release, it checks if the above key already implies a newer JRE version. If it is, the 6uX installer won't set the following key to 1: HKLM/SOFTWARE/JavaSoft/Java Plug-in/1.6.0_27/UseJava2IExplorer Note that the nightly build of 7u2 has a different problem due to bug in converting deploy.dll to be compiled with unicode enabled. The bug causes the TreatAs key not being created during installation and masking this bug. Fixing all the above issues in 7u2.

WORK AROUND install JDK 7 back works fine again.