[abc-users] Problems weaving JDK classes

From: Alex Villazon <alex.villazon_at_lu.unisi.ch>
Date: Wed, 7 May 2008 18:39:27 +0200


     I'm trying to weave an aspect to JDK classes with abc, but I have
some problems.

     We have a framework that allows instrumentation on JDK classes
called FERRARI http://www.inf.unisi.ch/faculty/binder/documents/pppj07.pdf
that handles bootstrapping issues and we successfully woven several
aspects such as DJProf http://www.mcs.vuw.ac.nz/~djp/djprof/ using
AspectJ's ajc compiler into the JDK.

     Now, we want to adapt abc to our framework, but I have some
problems and very few debugging information to understand what is wrong.
(I'm using JDK1.5 on linux and the last release of abc)

    To simplify, I put in myrt.jar only java/util and try to weave
this simple aspect.

public final aspect Dummy {
  pointcut traced(): call(* *(..)) && !within(Dummy);
   before(): traced() { System.out.println("traced");}

  This works almost without problem ( I had to remove from myjar java/
util/Formatter*, java/util/ResourceBundle* and java/util/regex/
Pattern* because of the following errors reported by abc
Formatter.java:2309: The exception java.lang.Throwable must be either
     or declared to be thrown
ResourceBundle.java:1101: The exception java.lang.Throwable must be
     caught or declared to be thrown
Pattern.java:5080: The exception java.lang.Throwable must be either
caught or
     declared to be thrown

  After removing these files, abc was able to weave the aspect to

  Then, I added to my Dummy aspect the following declaration (that
uses java.util classes which I'm weaving...)

  static private Set _refs = new HashSet();

This time, abc failed to compile even the aspect itself...

  abc -verbose -injars myrt.jar -sourceroots simpleabc/ -outjar
abc started on Wed May 07 16:46:06 GMT+01:00 2008
     The type of the variable initializer "java.util.HashSet" does not
     that of the declaration "java.util.Set".
     static private Set _refs = new HashSet();
1 error.

  My questions are question:

- Is there some restriction on abc to compile JDK classes?

- Could it be that the compiler has some conflicts because the classes
java.util.Set and java.util.HashSet used to compile the aspect are not
those from the original rt.jar but those that will be woven from
myrt.jar ?

   Curiously, when I removed java.util.Set from myrt.jar, then the
aspect was woven correctly. (nornally Set is an interface and should
not be woven..)

  I also tried to tell polyglot to use the original rt.jar with
+polyglot -bootclasspath $JAVA_HOME/jre/lib/rt.jar -polyglot but it
does not work.

Any help will be strongly appreciated,


Received on Wed May 07 2008 - 17:39:51 BST

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