import java.lang.reflect.*;

public class ReflectionExample {
    public static void main(String[] args) {
        try {
            // same as Object fooObject = new Foo("Hello World", new Integer(37)); ...
            Class fooClass = Class.forName("Foo");
            Class[] paramTypes = {Class.forName("java.lang.String"),
                                  Class.forName("java.lang.Integer")};
            Constructor con = fooClass.getConstructor(paramTypes);
            Object[] paramValues = {"Hello World", new Integer(37)};
            Object fooObject = con.newInstance(paramValues);

            Method[] methods = fooClass.getDeclaredMethods();
            System.out.println("Foo has the methods:");
            for (int i = 0; i < methods.length; i++) {
                System.out.println("  " + methods[i].getName());
            }

            // same as System.out.println(fooObject.toString()); ...
            Class[] methodParamTypes = {};
            Object[] methodParamValues = {};
            System.out.println(fooClass.getMethod("toString",
                    methodParamTypes).invoke(fooObject,methodParamValues));


            // same as ((Foo) fooObject.setValue(3));
            Class[] methodParamTypes2 = {Integer.TYPE};  // same as int.class
            Method setValueMethod = fooClass.getMethod("setValue",
                     methodParamTypes2);
            Object[] methodParamValues2 = {new Integer(2)};
            setValueMethod.invoke(fooObject,methodParamValues2);

            System.out.println(fooObject.toString());

        } catch (Exception e) {
            e.printStackTrace();
        }
        try {
            System.in.read();   // waits for the user to press "Enter"
        } catch (Exception e2) {
            e2.printStackTrace();
        }
    }
}

class Foo {
    String message;
    Integer value;



    public Foo(String message, Integer value) {
        this.message = message;
        this.value = value;
    }

    public void setValue(int x) {
        value = new Integer(x);
    }

    public String toString() {
        return message + " " + value;
    }
}