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  1. JDK
  2. JDK-6788525

BeanInfo.getPropertyDescriptors() gets mixed up with generic bridge methods

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    • Subcomponent:
    • CPU:
      x86
    • OS:
      windows_xp

      Description

      FULL PRODUCT VERSION :
      java version "1.6.0_05"
      Java(TM) SE Runtime Environment (build 1.6.0_05-b13)
      Java HotSpot(TM) Client VM (build 10.0-b19, mixed mode)


      ADDITIONAL OS VERSION INFORMATION :
      Microsoft Windows XP [versão 5.1.2600]

      A DESCRIPTION OF THE PROBLEM :
      If a JavaBean class has properties that are inherited from a generic superclass, java.beans.BeanInfo will find a PropertyDescriptor corresponding to synthetic bridge methods and not the actual typed methods.

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Create a generic superclass with a property (getter/setter pair) whose type is a type parameter. Create a parametrized subclass (a subclass with actual type arguments). Use java.beans.Introspector.getBeanInfo() to get a BeanInfo representing the subclass. Notice that the PropertyDescriptor that would correspond to the property (meaning, it's name is the same as the name of the property) has a type equal to the upper bound of the type parameter in the superclass, where we would expect it to have the corresponding type argument defined on the subclass.

      This behavior is likely due to the Introspector finding synthetic bridge methods for the getter and setter instead of the actual methods.

      (The Expected and Actual results below refer to the output of the sample code)

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      class of type class java.lang.Class
      foo of type class java.lang.String

      ACTUAL -
      class of type class java.lang.Class
      foo of type class java.lang.Object


      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.beans.*;

      class Super<T> {
      public T getFoo() {return null;}
      public void setFoo(T t) {}
      }

      class Sub extends Super<String> {
      }

      public class Main {
      public static void main(String[] args) throws IntrospectionException {
      BeanInfo beanInfo = Introspector.getBeanInfo(Sub.class);

      PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();

      for (PropertyDescriptor prop : propertyDescriptors) {
      System.out.printf("%s of type %s\n", prop.getName(), prop.getPropertyType());
      }
      }
      }
      ---------- END SOURCE ----------

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              Assignee:
              serb Sergey Bylokhov
              Reporter:
              igor Igor Nekrestyanov (Inactive)
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