Constructor in Anonymous Inner Class

Recently, I've been playing with JMockit, and I've come across certain language constructs in java that confused me.

It appears they were related to creating a different body for a constructor in the inner anonymous class. Which is hard to do, as the name of the Anonymous Inner Class is unknown.

package mrbean.anonymous;

public class Anonymous 
{

  private int i = 5;

  public int getI() 
  {
    System.out.println(this + " getI");
    return i;
  }

  public void setI(int i) 
  {
    System.out.println(this + " setI");
    this.i = i;
  }

  public Anonymous() 
  {
    System.out.println(this + " Constructor");
  }

  public void doStuff() 
  {
    System.out.println(this + " doStuff");
    System.out.println("i=" + new Anonymous() {
      {
        System.out.println(this + " Anonymous Constructor");
        setI(10);
      }
    }.getI());
  }

  /**
   * Main method to start the program.
   * @param args arguments
   */
  public static void main(String[] args) 
  {
    System.out.println("main: Start program.");
    Anonymous first = new Anonymous();
    System.out.println("main: i=" + first.getI());
    first.doStuff();
    System.out.println("main: End program.");
  }

}

This provided me with the following output:

main: Start program.
mrbear.anonymous.Anonymous@7d8a992f Constructor
mrbear.anonymous.Anonymous@7d8a992f getI
main: i=5
mrbear.anonymous.Anonymous@7d8a992f doStuff
mrbear.anonymous.Anonymous$1@23fc4bec Constructor
mrbear.anonymous.Anonymous$1@23fc4bec Anonymous Constructor
mrbear.anonymous.Anonymous$1@23fc4bec setI
mrbear.anonymous.Anonymous$1@23fc4bec getI
i=10
main: End program.

Especially in the creation of Expectations and Verifications in test methods in JMockit, it's quite common.