Listing B: MemoryBlock.java
public class MemoryBlock {
 int id;
 int size;
  byte[] block;

  public MemoryBlock( int id, int size ) {
   this.id = id;
   this.size = size;
    block = new byte[size];
   System.out.println( "MemoryBlock created: "+this );
  }

  public String toString() {
    return "{id="+id+",size="+size+"}";
  }

  protected void finalize() {
   System.out.println( "MemoryBlock finalized: "+this );
  }
}