Using Java Reflections to retrieve member classes

Question

Hi All,

I am using .getDeclaredClasses() method to retrieve all the classes that have been defined in object. However, I am not able to retrieve anonymous classes defined in the class. Here is the code sample that I am testing:

public class TempCodes
{
  public static void main(String[] args)
  {
    Ball b = new Ball()
    {
      public void hit()
      {
        System.out.println("You hit it!");
      }
    };
    b.hit();
  }

  interface Ball {
    void hit();
  }
}

and this is what my code does:

  memClass = className.getDeclaredClasses();
  if (memClass .length > 0) 
  {
        for (int index = 0 ; index < memClass .length ; index++)
        {
            System.out.println("\t\t\t" + memClass [index]);
        }
  }

Can anyone help me understand how to retrieve the anonymous class?

Regards, darkie

Answer 1

With little help of the classpath:

final Class<?> cls = TempCodes.class;
String[] names = new File(cls.getResource("").toURI()).list(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        return name.startsWith(cls.getSimpleName());
    }
});
for (String name : names) {
    System.out.println(name);
}

Result:

TempCodes$1.class
TempCodes$Ball.class
TempCodes.class

You've to filter the desired information out yourself.

Disclaimer: doesn't work well with JAR files, but the hint is clear enough: it's not possible with reflection. I would question the need for this and rethink the design or approach. Here are some topics of interest: Java reflection: How can I retrieve anonymous inner classes? and Accessing inner anonymous class members.