Michael Nascimento Santos's Blog

Bizarre behaviour in PropertyDescriptor

import java.beans.*;

public class BizarreBean {
   public static class B1 {
      public String getProperty() {
         return null;
      }
   }

   public static class B2 extends B1 {
      public String getProperty() {
         return null;
      }
   }

   public static void main(String[] args) throws Exception {
      PropertyDescriptor[] pd = Introspector.getBeanInfo(B2.class)
            .getPropertyDescriptors();

      for (int i = 0; i < pd.length; i++) {
         if (!pd[i].getName().equals("property")) {
            continue;
         }

         System.out.println(pd[i].getReadMethod());
         break;
      }
   }
}

public java.lang.String BizarreBean$B2.getProperty()

   public static class B1 {
      public String getProperty() {
         return null;
      }

      public void setProperty(String property) {
      }
   }

   public static class B2 extends B1 {
      public String getProperty() {
         return null;
      }

      public void setProperty(String property) {
      }
   }

public java.lang.String BizarreBean$B1.getProperty()

Comments

• Cool!

  Anyway, J2SE 5.0 handles well this code.

  Posted by: rafaelsteil on November 29, 2004 at 11:52 AM

• I've found the PropertyDescriptor class to be among the poorest in the Java libraries. I've never managed to get it's bean-name constructor PropertyDescriptor(String propertyName, Class beanClass) to work with read-only properties.

  In frustration I had to create my own class, BeanProperty.java, that does the same thing.

  Posted by: jessewilson on November 29, 2004 at 03:03 PM

• I am glad Tiger handles it properly, but it could be fixed on 1.4.2 as well.

  Posted by: mister__m on November 29, 2004 at 03:15 PM

• most bizarre bug? At least it is not very old.
  With javax.comm, try to put parallel port in bi-direcional mode and you´ll see the oldest bug in Java.
  

  Posted by: lucabastos on November 30, 2004 at 05:25 AM

• This was a bug in 1.4.2_xx but has been fixed in 1.4.2_06 and in 1.5. No need to file a bug. See 4918902 for details.

  The most bizzare bug in 5 years? Clearly you haven't poked around enough. I've seen bugs in Java that make grown men weep ;-)

  Posted by: davidson1 on November 30, 2004 at 01:03 PM

• That

  Posted by: igborba on November 30, 2004 at 05:44 PM

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