Generate class files that target a specified version of the
VM. Class files will run on the specified target and on later
versions, but not on earlier versions of the VM. Valid targets are
1.1 1.2 1.3 1.4 1.5 (also
5) and 1.6 (also 6).
The default for -target depends on the value of
If -source is not specified, the value of -target is
If -source is 1.2, the value of -target is 1.4
If -source is 1.3, the value of -target is 1.4
For all other values of -source, the value of -target is
the value of -source.