On Mon, Oct 28, 2013 at 12:55 PM, Kohsuke Kawaguchi
> we can tweak the RemoteClassLoader so that it'd warn us if we
> try to load Java7 classes inside Maven JVM.
As I just mentioned, the remoting library can already do this. (I
wrote the hook months ago.) It just needs to be activated in
maven-plugin. The code to do so is commented out because it was not
clear to me that we wanted to forbid Java 7-specific classes from
being loaded from plugins, if they are advertised as being for Java
7+. The same decision applies to the slave channel: it would be a
one-line change to prevent Java 7 bytecode from being loaded on
slaves, but this might block deliberate usage of plugins with known 7+
dependencies. But the positive side is that we would immediately know
if 7+ bytecode dependencies were *accidentally* introduced in plugins.
We would also know if 7+ bytecode from servlet containers was
“leaking” through the remoting channel.
Perhaps Slave should have an optional NodeProperty to restrict
bytecode level? Then a user who suspects a problem with accidental 7+
dependencies could check the box to enforce 6+ compatibility, and get
a clear error message rather than the opaque ClassFormatError they