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  1. JDK
  2. JDK-4619536

Introspector mixes property types in IndexedPropDesc's w/ inherited info

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    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: 1.4.0, 1.4.2, 5.0
    • Fix Version/s: 5.0
    • Component/s: client-libs
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b28
    • CPU:
      generic, x86, sparc
    • OS:
      generic, linux, solaris_2.6, windows_2000

      Description

      Name: nt126004 Date: 01/04/2002


      java version "1.4.0-beta3"
      Java(TM) 2 Runtime Environment, Standard Edition (build
      1.4.0-beta3-b84)
      Java HotSpot(TM) Client VM (build 1.4.0-beta3-b84, mixed
      mode)


      Full Operating System Version :

      GLibC 2.1.3, kernel 2.2.12, RHL 6.1


      A description of the problem :
      Under some circumstances, it is possible for Introspector to
      create an IndexedPropertyDescriptor which has inconsistent
      types for the regular and indexed versions of the accessor.

      Specifically: if a superclass provides an indexed property
      with an indexed getter and a subclass provides a nonindexed
      getter with the same name, an IndexedPropertyDescriptor will
      be created by the default Introspector which has
      inconsistent property types for PropDesc.getPropType vs.
      IdxdPropDesc.getIdxdPropType.

      Originally observed in NetBeans IDE. A class extending
      JPanel had a method public Component getComponent (to
      implement some random interface). Selecting the source and
      choosing Customize Bean, which is supposed to open a
      property sheet permitting its properties to be edited and an
      instance serialized, threw an exception: reported as #17728
      on www.netbeans.org and worked around (see below). The
      problem was that Container.getComponent(int) and Component
      org.netbeans.core.ui.IDESettingsPanel.getComponent() were
      mashed into the same (indexed) prop desc; the property sheet
      code in NetBeans saw an IndexedPropertyDescriptor with a
      getPropertyType, assumed it would be an array type according
      to the JavaBeans spec, and tried to use it an array, and
      failed.

      Including simpler test case showing that the two types need
      not be related. Here Date B.foo is unrelated to the indexed
      int A.foo[]. It is a bug in Introspector to put them both in
      the same property. Since a bean can have only one property
      with a given name, it ought to hide int A.foo[] and return a
      plain PropertyDescriptor, type Date, name foo, getter public
      Date B.foo(), no setter.

      #4477877 reported a number of problems with Introspector,
      but these had to do with unreproducible load order. This is
      different, it is reproducible as far as I know. #4168833 is
      very similar, but not identical, to this bug.

      Occurs in both 1.3.1_01 and 1.4 beta 3.

      Steps to follow to reproduce the problem :
      1. Compile and run the included test class.

      Expected versus actual behavoir :
      Actual results:

      ---%<---
      prop: class<class java.lang.Class>
      public final native java.lang.Class
      java.lang.Object.getClass()
      null
      indexed prop: foo<class java.lang.String>
      public java.lang.String Test17728$A.getFoo(int)
      null
      regular prop info also:
      prop: foo<class java.util.Date>
      public java.util.Date Test17728$B.getFoo()
      null
      ---%<---

      Expected results:

      ---%<---
      prop: class<class java.lang.Class>
      public final native java.lang.Class
      java.lang.Object.getClass()
      null
      prop: foo<class java.util.Date>
      public java.util.Date Test17728$B.getFoo()
      null
      ---%<---


      This bug can be reproduced always.

      ---------- Begin Source ----------
      import java.beans.*;
      import java.util.Date;
      public class Test17728 {
          public static void main (String args[]) throws Exception
      {
              BeanInfo y = Introspector.getBeanInfo(B.class);
              PropertyDescriptor[] p = y.getPropertyDescriptors();
              for (int i = 0; i < p.length; i++) {
                  if (p[i] instanceof IndexedPropertyDescriptor) {
                      IndexedPropertyDescriptor ipe =(IndexedPropertyDescriptor)p[i];
                      System.out.println("indexed prop: " +ipe.getName() + "<" + ipe.getIndexedPropertyType() + ">");
                      System.out.println("\t" +ipe.getIndexedReadMethod() + "\n\t" +ipe.getIndexedWriteMethod());
                      System.out.println("regular prop info also:");
                  }
                  System.out.println("prop: " + p[i].getName() +"<" + p[i].getPropertyType() + ">");
                  System.out.println("\t" + p[i].getReadMethod() +"\n\t" +p[i].getWriteMethod());
              }
          }
          public static class A {
              public String getFoo(int x) {return null;}
          }
          public static class B extends A {
              public Date getFoo() {return null;}
          }
      }

      ---------- End Source ----------

        Customer Workaround :
      Work around (used in NetBeans' org.openide.nodes.BeanNode):
      after getting PropertyDescriptor's from
      Introspector.getBeanInfo, clean them up: if there are any
      IndexedPropertyDescriptor's where getPropertyType() is not
      null and yet not an array type, throw them out (ignore those
      properties). Does not let the subclass property be used, but
      at least prevents class cast exceptions and so on.
      (Review ID: 137384)
      ======================================================================

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              Assignee:
              mdavidsosunw Mark Davidson (Inactive)
              Reporter:
              nthompsosunw Nathanael Thompson (Inactive)
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