Why can assignment from one type to the same need checking?

Question

I'm running IntelliJ's Code Analyzer (IntelliJ 11.1.4) on a class and am getting this warning:

Unchecked assignment: 'java.util.List' to 'java.util.List '

The code it complains about is:

List<String> targetDocumentIds = pepperWorkflowInstance.getTargetDocumentIds();

For reference:

public class PepperWorkflowInstance<T extends PepperWorkflowInstanceData> implements Serializable {

   private List<String>            targetDocumentIds = new ArrayList<String>();
   ...
   public List<String> getTargetDocumentIds() {
      return targetDocumentIds;
   }
   ...
}

So the types match... so why would I need to 'check' the assignment?

What type is targetDocumentIds from pepperWorkflowInstance instance? — jn1kk
– jn1kk, Commented Nov 20, 2012 at 16:31
Just realized this is a IntelliJ warning, not JVM. What version of IntelliJ do you have? — jn1kk
– jn1kk, Commented Nov 20, 2012 at 16:35
@Luciano I haven't, but I'd like to confirm that I'm not missing something in Java, first — Dancrumb
– Dancrumb, Commented Nov 20, 2012 at 16:49

tcb · Accepted Answer · 2012-12-28 18:15:25Z

1

Make sure that pepperWorkflowInstance has parameter:

pepperWorkflowInstance = new PepperWorkflowInstance<SomeClass>();

See IDEA-6254.

answered Dec 28, 2012 at 18:15

tcb

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Comments

Pawel Solarski · Accepted Answer · 2012-11-20 16:39:57Z

0

If the pepperWorkflowInstance is of super class where raw type is used as return type, then that may generate that message.

Example.

class A{
    public List getTargetDocumentIds(){
        return new ArrayList();
    }
}

class B extends A{
    public List<String> getTargetDocumentIds(){
        return new ArrayList<String>();
    }
}

public class Tester {

    public static void main(String[] args) {
        A a = new B();
        List<String> targetDocumentIds = a.getTargetDocumentIds(); 
        // above produces compiler type safety warning                        
    }
}

answered Nov 20, 2012 at 16:39

Pawel Solarski

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1 Comment

Dancrumb Over a year ago

Thanks, but I'm not sure that applies to my situation... good info though.

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