Comment 8 for bug 1448548

cautious-launcher is an Ubuntu-specific helper that ensures .jar files have the required executable bit set in order to comply with the following:

https://wiki.ubuntu.com/SecurityTeam/Policies#Execute-Permission_Bit_Required

The problem with openjdk is with this section in the rules file:

# .desktop files need to be multiarch installable
java_launcher = /$(basedir)/bin/java
java_launcher = /usr/bin/java
ifeq ($(distribution),Ubuntu)
  ifeq (,$(filter $(distrel),karmic jaunty intrepid hardy))
    java_launcher = cautious-launcher %f /$(basedir)/bin/java
    java_launcher = cautious-launcher %f /usr/bin/java
  endif
endif

I'm not sure why java_launcher is getting set twice, and I'm not sure why we're limiting cautious-launcher to older ubuntu releases.