--- ab.java -------------------------------------------------
public class ab {
  public int a;
  public int b;
  public ab(int x, int y){
    a = x;
    b = y;
  }
  public ab() { a = 1; b = 1; }
  public int getA() { return a; }
  public void setA(int x) { a = x; }
  public int plus() { return a + b; }
  public void print() {
    System.out.println("a="+a+",b="+b);
  }
}

--- report.java ----------------------------------------------
import java.lang.reflect.*;

public class report {
  public static void main(String argv[]){
    Class cls;
    try {
      cls = Class.forName("ab");
    } catch(Exception e){
      System.out.println("cannot instantiate class");
      return;
    }
    try {
      System.out.println("Field:");
      Field fields[] = cls.getDeclaredFields();
      for(int i = 0; i < fields.length; i++){
	System.out.println(" "+fields[i].toString());
      }
    } catch(Exception e){
      System.out.println("exception!!!");
      return;
    }
  }
}

---- test.java ---------------------------------------------  
import java.lang.reflect.*;

public class test {
  public static void main(String argv[]){
    Class cls;
    Object obj;
    try {
      cls = Class.forName("ab");
    } catch(Exception e){
      System.out.println("cannot instantiate class:"+e);
      return;
    }

    try {
      Field a = cls.getField("a");
      Field b = cls.getField("b");

      Class pTypes1[] = { Integer.TYPE, Integer.TYPE };
      Constructor Cons = cls.getConstructor(pTypes1);

      Class pTypes2[] = { Integer.TYPE };
      Method setA = cls.getMethod("setA",pTypes2);
      
      Class pTypes3[] = { };
      Method getA = cls.getMethod("getA",pTypes3);
      Method plus = cls.getMethod("plus",pTypes3);
      Method print = cls.getMethod("print",pTypes3);

      Object VOID[] = { };

      Object args[] = { new Integer(20), new Integer(1) };
      obj = Cons.newInstance(args);

      System.out.println("a="+a.getInt(obj));
      System.out.println("b="+b.getInt(obj));

      a.setInt(obj,10);
      print.invoke(obj,VOID);

      System.out.println("a="+a.getInt(obj));
      System.out.println("b="+b.getInt(obj));

      Object o = plus.invoke(obj,VOID);
      System.out.println("a+b="+((Integer)o));

    } catch(Exception e){
      System.out.println("exception!!! "+e);
      return;
    }
  }
}