FrenchPress Gives Students Automated Feedback on Java']Java Program Flaws

We created an Eclipse plug-in called FrenchPress that partially automates the task of giving students feedback on their Java programs. It is designed not for novices but for students taking their second or third Java course: students who know enough Java to write a working program but lack the judgment to recognize bad code when they see it. FrenchPress does not diagnose compile-time or runtime errors, or logical errors that produce incorrect output. It targets silent flaws, flaws the student is unable to identify for himself because nothing in the programming environment alerts him. FrenchPress diagnoses flaws characteristic of programmers who have not yet assimilated the object-oriented idiom. Such shortcomings include misuse of the public modifier, fields that should have been local variables, and instance variables that should have been class constants. Other rules address the all too common misunderstanding of the boolean datatype. FrenchPress delivers explanatory messages in a vocabulary appropriate to the student's current level. This paper reports preliminary results of a formative evaluation of FrenchPress conducted in a Fall 2014 data structures and algorithms course. User satisfaction survey responses indicate that among the students who received substantive diagnostic suggestions from FrenchPress, the percentage who were motivated to modify their program varied from 36% to 64% on four different assignments.