Ext plugin should never create empty jar files

• Type: Bug
• Status: Closed
• Resolution: Fixed
• Affects Version/s: 6.0.3 GA
• Fix Version/s: 6.0.4 GA
• Component/s: Legacy > Extension Environment
• Labels: None
• Branch Version/s:
  6.0.x, 5.2.x, 5.1.x
• Backported to Branch:
  Committed

Empty jar files cause errors in Tomcat. Don't use the zip task, use the jar task to ensure MANIFEST.MF exists in ext jars.