#13 Check Java dependencies for RPMs (OpenJDK, gcj)

[Mihai T. Lazarescu]

yum pulls by default a version of Java which crashes ZGRViewer.

Make sure it pulls the right one.

Check also if Oracle Java binary can be freely redistributed with ParTools.

[Mihai T. Lazarescu]

ZGRViewer apparently works with Oracle Java and OpenJDK.

Currently it crashes with GCJ.

ParTools RPM should require either:

** 'xml-commons-apis' for Oracle Java;

** 'jre-openjdk' for OpenJDK.

Check for version >= 1.6 won't hurt, either.

Then, the post-install scripts should check that alternatives
select the right Java VM.

ZGRViewer launch script should recheck at every run.
Add dependency on zenity to notify the errors.

[Mihai T. Lazarescu]

Better always require OpenJDK regardless of Oracle Java.

Also, check that OpenJDK is what we get from alternatives. :-)