http://java.sun.com/j2se/1.5.0/install-solaris.html#install-pkg

Step 5 states, "Version 1.5.0 will automatically become the default Java platform on Solaris 9 or 10..." Version 1.4.2 is currently the default Java for Solaris 9. (To be specific, it is one of the 1.4.2_0x updates, but I'm not sure which.) This will change when S9 is updated to the JDS, but as of now, tiger is not the default.

http://java.sun.com/j2se/1.5.0/install-solaris.html#defaultinstallations

This also shows the wrong default Java for Solaris 9.