How to interpret the Classpath-Exception?

[Clemens Eisserer]

 Hi,

To make it short - lets say someone (not me or anyone I am doing
business with) would port OpenJDK to a new embedded OS (not using the
Java or OpenJDK trademark) and does not (want to) open-source this new
port.
The argument against open-sourceing the OS specific code is, that
thanks to OpenJDKs fine platform abstraction, the new code required to
support the new OS would not touch any existing OpenJDK code but
instead extend it in various places (by inheriting from predefined
classes like GraphicsEnvironment, Graphics, etc and by implementing
"native" functions).

Is this actually considered legal by the GPL+classpath exception
license? I read the classpath-exception up and down, but didn't come
to a conclusion.
I guess it all boils down to whether the OS-specific implementations
count as "independent modules" as stated by the classpath exception:
"permission to link this library with independent modules to produce
an executable, regardless of the license terms of these independent
modules,"

Is this point of view valid or misinterpreting the license?

Thanks & best regards, Clemens