Daily trawl through the java.blogs feeds picked up a reference to ONJava.com: SSS (Small, Simple, Safe) [May. 26, 2004]. SSS is apparently a simple tool that allows you to instantiate and play with Java objects. It is apparently used and useful in teaching. I simply had to make a comment to the effect that BlueJ has had this feature for ever! Here’s my reponse in full:
BlueJ is a simple Java IDE (avalable from http://www.bluej.org) which also has this sort of behaviour. You can instantiate an object of any class on the classpath by providing the fully qualified name and then selecting any of the class’s constructors. Once the object has been instantiated and a small icon (sort of like a UML object diagram) appears. You can then right-click on the “object” to call any of the object’s methods. Because BlueJ is an IDE and debugger it has privileged access to the JVM, which allows you to also inspect the object to see all its private state.
BlueJ has built up quite a following in the educational arena just lately and there are several “CS101″ text books using it (but none from O’Reilly). See the web site quoted above for more info and access to the lively discussion lists.
It’ll be interesting to see if there is any feedback!