Specifiy both source ant target Java versions
...when compiling Java code. Since `stx:libjava` only supports Java 7,
make sure all code is compiled targeting Java 7.
<?xml version="1.0" encoding="UTF-8"?>
<projectDescription>
<name>stx.libjava</name>
<comment></comment>
<projects>
</projects>
<buildSpec>
<buildCommand>
<name>org.eclipse.jdt.core.javabuilder</name>
<arguments>
</arguments>
</buildCommand>
</buildSpec>
<natures>
<nature>org.eclipse.jdt.core.javanature</nature>
<nature>org.apache.ivyde.eclipse.ivynature</nature>
</natures>
</projectDescription>