Re: Compiling 5.0 syntax java files
Philipp wrote:
In my eclipse project's "Properties" page on the "Java Compiler" node,
if I choose ".class file compatibility 1.3" and "source compatibility
6.0" I get an error "Classfile compatibility must be greater or equal
than source compatibility".
If I understood correctly your linked page, there shouldn't be any
error... Where am I wrong?
The class file version must be at least the source version. That's because
later language versions, e.g., Java 5, introduced keywords like 'enum', and
changed some things about how class files load and so forth. Earlier language
versions like 1.3 will not be able to deal with these new class file features.
If the source code is earlier, e.g., a version 1.3 source, then all you have
watch out for is newly-illegal use of keywords like 'assert' or 'enum'. Newer
Java versions can deal with the older class-file versions just fine. So Java
1.3 source is all right with Java 6 class files, but not the other way around.
You really should work with Java 5. The use of 'assert', 'enum', generics and
the new for-loop syntax is worth it. You also get some lovely API upgrades
like the java.util.concurrent package, and the superior semantics of the
memory model and other things really help also.
--
Lew