Unit 6: Objects That Behave Well

Unit 5 left two embarrassments in place. Printing an object produces machine noise, and two objects holding identical values report that they are different. This unit pays both debts by making students see the failure before they get the fix. They print their own Unit 5 object and copy the actual output by hand, then build two objects with identical fields, compare them with == and record that the answer is false. Only then do toString and equals arrive, along with what sameness should mean for this particular class, the exact signature Java expects, naming conventions as a working requirement, and what makes a class usable by somebody else.

The performance task is The Class Somebody Else Can Use. Students give their Unit 5 class a toString and an equals, write a one page usage sheet, and hand both to a classmate who must write a working program with them and may not ask the author a single question. The author records every place the classmate got stuck and then revises. The heaviest criterion is that the classmate succeeded on the documentation alone and the author made at least one named revision because of what the classmate could not figure out.

Overriding is named honestly and not explained away. Students write a method Java uses in place of one it already gave their class, the word for that is stated, and Unit 9 is named as where the machinery is taught. A teacher gets a plan and a substitute plan for each of the fifteen lessons, answer keys, tiered handouts, and both classroom demonstrations written as student run activities rather than teacher shown ones.

The unit runs 15 instructional days.