Just recompiled SparseArray. No changes made to code.
Made a few small adjustments to the answer for Q1. This document is ready to submit.
Major overhaul of the unit test for this class. Compiles and runs successfully as written.
Removed all instances of getCursor() function (+definition). Now the only way to navigate using the cursor is through goLeft/Right/Sibling/ and root/parent
Removed unnecessary import statements.
Uncommented the try/catch sections of the unit test--everything works! Okay, I think this document is ready for submission!
Ooops. Now I've removed my TO DO comments. Now, ready for submission.
Major overhaul of the unit test. Compiles and runs successfully.

No major changes to the algorithms. (maybe there should be?)

Also, calls to toString() and has() don't work, so I've removed them.
Is this a good idea?
Removed unnecessary import statement.
Added postcondition to setItemAtIndex.