[Jikesrvm-core] [ jikesrvm-Bugs-1264431 ] JikesRVM doesn't initialize interfaces of a class

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Bugs item #1264431, was opened at 2005-08-19 18:13
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Category: runtime
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Jeremy Brown (jhbrown94)
Assigned to: Nobody/Anonymous (nobody)
Summary: JikesRVM doesn't initialize interfaces of a class

Initial Comment:
When JikesRVM initializes a class, it initializes that class's superclass, 
but not the class's interfaces.  This can cause static constant fields of 
those interfaces to remain uninitialized even though they are used. 

I've got a demo which, if compiled with jikes or with 'javac -target
1.4' will cause JikesRVM to abort with an exception, but compiled with
'javac -target 1.2' will work.  

The demo is this, put in a file called TestImpl.java:
------------------------------------------------------------
interface DummyIF {static final Integer BASE_FIELD = new Integer(6);}
public class TestImpl implements DummyIF {
    public static final int TEST_FIELD = BASE_FIELD.intValue();
    public static void main(String argv[]) {
	System.out.println("Value: " + TEST_FIELD);
    }
}
------------------------------------------------------------

The execution exhibits the bug like so:
------
> javac -target 1.2 TestImpl.java
> rvm TestImpl
Value: 6
> javac -target 1.4 TestImpl.java
> rvm TestImpl
Exception in thread "main": java.lang.ExceptionInInitializerError: While 
initializing TestImpl
        at com.ibm.JikesRVM.classloader.VM_Class.initialize(VM_Class.
java:1414)
Caused by: java.lang.NullPointerException
        at TestImpl.<clinit>(TestImpl.java:5)
        at com.ibm.JikesRVM.classloader.VM_Class.initialize(VM_Class.
java:1410)
JikesRVM: exit 113
------

The source of the difference seems to be that at 1.2, the constant
pool entry for BASE_FIELD in TestImpl.class refers to it as DummyIF.
BASE_FIELD, whereas with 1.4 (or with jikes, which defaults to 1.4 
semantics) the entry in TestImpl.class refers to it as TestImpl.
BASE_FIELD.  In the latter case, in JikesRVM 'fieldRef.
needsDynamicLink(method)' returns false, which causes DummyIF 
never to get initialized.

I am attaching a very simple patch which fixes the problem on the 
demo above.  I am running the sanity regression tests now on my 
600Mhz IA32 box, but they may take awhile to finish.


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