On 3/10/2011 6:54 PM, David Holmes wrote:
Andrew,
Just picking up on your SA comments and adding in the servicability folk and bcc'ing the build
folk ...
Dr Andrew John Hughes said the following on 03/11/11 10:46:
Well HotSpot is one thing I think works well as a separate repository.
It allows us to have a stable branch for OpenJDK6 for example. The only
real thing that stops it being independent is the servicability agent,
which, IME, would be better held in the JDK. That would also mean that
the existing rules for building java classes could be used, rather than
reinventing it all in the HotSpot makefiles as at present.
The SA is part of Hotspot because the SA is a Java interface to the Hotspot internals. Hence the
SA Java files have to be updated when the hotspot source files are, hence they must be in the same
repo or we'd have huge coordination problems. These files reside in sa-jdi.jar
The SA classes are dependent on the com.sun.jdi interfaces/classes, so yes changes to JDI might
require changes to the SA. But the SA is just a JDI client in that regard.
See also CR
6599669: SA-JDI: Fix to work with HotSpot Express.
It points out:
The HotSpot workspace includes the Serviceability Agent .java files.
These files must be kept in sync with HotSpot changes.
The HotSpot workspace also includes an (read-only) implementation of JDI
using SA called SA-JDI. These files must implement new features
as they are added to JDI in new feature releases. So, what happens
to these new features when SA-JDI is built/used in an update release
as part of HotSpot Express?
- jjh
I've already run across one place where this is true. HotSpot builds
the servicability agent with -source 1.4 -target 1.4. Why? Because
of incompatibilies between its implementation and the com.sun.jdi
interfaces which require Comparable<T> not Comparable.
My understanding is that the SA classes define their own Enum type which conflicts with the
java.lang.Enum added in 1.5. To avoid all the warnings this would generate, plus the raw type
warnings as the SA is not generified, it is compiled with -source 1.4.
David
