Re: [aspectj-users] null thisJoinPointStaticPart when advising construc

[Andy Clement <andrew.clement@xxxxxxxxx>]

Here is some pure Java code that shows what you are hitting:
---
public class A {
  public static void main(String []argv) {
    new C();
  }
  static String get() { return "abc";}
}

class B {
  static C b = new C();
}

class C extends B {
  final static String str = A.get();

  public C() {
    System.out.println(str);
  }
}
---
when run it prints:
null
abc

This is because a condition of initializing C is that B is
initialized.  B's static initializer will call back to C - which
hasn't had the initializer run yet, so the field 'str' is null.  If I
replace 'str' with thisJoinPointStaticPart, then that is the problem
AspectJ is triggering with the code it is creating.

Andy

On 18 March 2010 14:35, Hagai Cibulski <hagaic@xxxxxxxxx> wrote:
> Here is a variation on your program that recreates the problem:
>
>
>
> aspect Test {
>
>       public static void main(String[] argv) {
>
>             new C();
>
>       }
>
>
>
>       pointcut methodUnderTestExecution1() :
>
>             (execution(* *(..)) || execution(new(..))) && !within(Test);
>
>
>
>       before(): methodUnderTestExecution1() {
>
>             Object sig = thisJoinPointStaticPart.getSignature(); // null L
>
>             System.out.println(sig);
>
>       }
>
> }
>
>
>
> class B {
>
>       static C b = new C();
>
> }
>
> class C extends B {
>
> }
>
>
>
> -----Original Message-----
> From: aspectj-users-bounces@xxxxxxxxxxx
> [mailto:aspectj-users-bounces@xxxxxxxxxxx] On Behalf Of Andy Clement
> Sent: Thursday, March 18, 2010 10:20 PM
> To: aspectj-users@xxxxxxxxxxx
> Subject: Re: [aspectj-users] null thisJoinPointStaticPart when advising
> constructor execution
>
>
>
> Can you tell me what kind of constructors lead to that being null?  A
>
> simple (complete) program that fails would be great.  This program:
>
>
>
> ---
>
> aspect Test {
>
>   public static void main(String []argv) {
>
>     new C();
>
>   }
>
>
>
>  pointcut methodUnderTestExecution1() :
>
>             (execution(* *(..)) || execution(new(..))) && !within(Test);
>
>
>
>   before(): methodUnderTestExecution1() {
>
>         Object sig = thisJoinPointStaticPart.getSignature();
>
>       System.out.println(sig);
>
>   }
>
>
>
> }
>
>
>
> class C { }
>
> ---
>
>
>
> works fine and prints C().
>
>
>
> cheers
>
> Andy
>
>
>
> On 18 March 2010 13:09, Hagai Cibulski <hagaic@xxxxxxxxx> wrote:
>
>> Hi All!
>
>>
>
>> Could use some help here…
>
>>
>
>>
>
>>
>
>> I'm tracing methods execution stemming from JUnit tests using AspectJ,
>> using
>
>> the following pointcut:
>
>>
>
>>       pointcut methodUnderTestExecution() :
>
>>
>
>>             execution(* *(..))
>
>>
>
>>             && mutFilter();
>
>>
>
>>
>
>>
>
>> before(): methodUnderTestExecution() {
>
>>
>
>>             Signature sig = thisJoinPointStaticPart.getSignature();
>
>>
>
>>                         …
>
>>
>
>> So far, that works fine!
>
>>
>
>>
>
>>
>
>> However, when trying to add constructor execution to the pointcut, I get
>
>> some unexpected behaviors:
>
>>
>
>>
>
>>
>
>>       pointcut methodUnderTestExecution1() :
>
>>
>
>>             (execution(* *(..)) || execution(new(..)))
>
>>
>
>>             && mutFilter();
>
>>
>
>>
>
>>
>
>> before(): methodUnderTestExecution1() {
>
>>
>
>>             Signature sig = thisJoinPointStaticPart.getSignature();
>
>>
>
>>             // thisJoinPointStaticPart == null L
>
>>
>
>>                         …
>
>>
>
>>
>
>>
>
>> For some constructors in the application under test the advice causes
>
>> NullPointerException because thisJoinPointStaticPart == null
>
>>
>
>>
>
>>
>
>> Anyone?
>
>>
>
>>
>
>>
>
>>
>
>>
>
>> Thanks,
>
>>
>
>> Hagai
>
>>
>
>> _______________________________________________
>
>> aspectj-users mailing list
>
>> aspectj-users@xxxxxxxxxxx
>
>> https://dev.eclipse.org/mailman/listinfo/aspectj-users
>
>>
>
>>
>
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