exposing Java private fields with reflection

classes/private/Expose.java

@@ -0,0 +1,25 @@
+import java.lang.reflect.Field;
+
+public class Expose {
+
+	public static void main(String[] args) {
+		Confidential message = new Confidential("text you shoudn't see");
+		Field privateField = null;
+		try {
+			privateField = Confidential.class.getDeclaredField("secret");
+		}
+		catch (NoSuchFieldException e) {
+			System.err.println(e);
+			System.exit(1);
+		}
+		privateField.setAccessible(true); // break the lock!
+		try {
+			String wasHidden = (String) privateField.get(message);
+			System.out.println("message.secret = " + wasHidden);
+		}
+		catch (IllegalAccessException e) { 
+			// this will not happen after setAcessible(true)
+			System.err.println(e);
+		}	
+	}
+}