Inference of reference immutability in Java

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 81-83).Javari is an extension of Java that supports reference immutability constraints. Programmers write Javari type qualifiers, such as the readonly type qualifier, in their programs, and the Javari typechecker detects mutation errors (incorrect side effects) or verifies their absence. While case studies have demonstrated the practicality and value of Javari, a barrier to usability remains in the development process. A Javari program will not typecheck unless all the references in the APIs of libraries it uses are annotated with Javari type qualifiers. Manually converting existing Java libraries to Javari is both tedious and error-prone; the development process requires an automated solution. This thesis presents an algorithm for statically inferring reference immutability in Javari. The flow-insensitive and context-sensitive algorithm is sound and produces a set of qualifiers that typecheck in Javari. The algorithm is precise in that it infers the most readonly qualifiers possible; adding any additional readonly qualifiers will cause the program to not typecheck. A tool, Javarifier, implements this algorithm in order to infer the Javari type qualifiers over a set of class files. Javarifier can also insert these qualifiers into the corresponding source code, if the source code is available. Javarifier automatically converts Java libraries to Javari. Additionally, Javarifier eases the task of converting legacy programs to Javari by inferring the mutability of every reference in a program. In case studies, Javarifier correctly inferred mutability over Java programs of up to 110 KLOC.by Jaime QuinonezM.Eng

Ownership and Immutability Inference for UML-based Object Access Control

We propose a mechanism for object access control which is based on the UML. Specifically, we propose use of ownership and immutability constraints on UML associations and verification of these constraints through reverse engineering. These constraints inherently support software design principles, and impose requirements on the implementation that may help prevent serious program flaws. We propose implementation-level models for ownership and immutability that capture well the meaning of these concepts in design, and we develop novel static ownership and immutability inference analyses. We perform an empirical investigation on several small-to-large Java programs. The results indicate that the inference analyses are precise and practical. Therefore, the analyses can be integrated in reverse engineering tools and can help support effective reasoning about software quality and security.

Apparatuses and Methods for Producing Runtime Architectures of Computer Program Modules

Apparatuses and methods for producing run-time architectures of computer program modules. One embodiment includes creating an abstract graph from the computer program module and from containment information corresponding to the computer program module, wherein the abstract graph has nodes including types and objects, and wherein the abstract graph relates an object to a type, and wherein for a specific object the abstract graph relates the specific object to a type containing the specific object; and creating a runtime graph from the abstract graph, wherein the runtime graph is a representation of the true runtime object graph, wherein the runtime graph represents containment information such that, for a specific object, the runtime graph relates the specific object to another object that contains the specific object