Code theft is a threat for companies that consider code asa core asset. A birthmark can help them to prove codetheft by identifying intrinsic properties of a program. Twoprograms with the same birthmark are likely to share a com-mon origin. Birthmarking works in particular for code thatwas not protected by tamper-resistant copyright notices thatotherwise could prove ownership.We propose a dynamic birthmark for Java that observes howa program uses objects provided by the Java Standard API.Such a birthmark is difficult to foil because it captures the observable semantics of a program. In an evaluation, ourAPI Birthmark reliably identified XML parsers and PNGreaders before and after obfuscating them with state-of-the-art obfuscation tools. These rendered existing birthmarksineffective, such as the Whole-Program-Path Birthmark byMyles and Collberg

Interacting with objects often requires following a protocol—for instance, a specific sequence of method calls. These protocols are not always documented, and violations can lead to subtle problems. Our approach takes code examples to automatically infer legal sequences of method calls. The resulting patterns can then be used to detect anomalies such as “Before calling next(), one normally calls hasNext()”. To our knowledge, this is the first fully automatic defect detection approach that learns and checks method call sequences. Our JADET prototype has detected yet undiscovered defects and code smells in five popular open-source programs, including two new defects in ASPECTJ.

We present staged allocation, a technique for specifying calling conventions by composing tiny allocators called stages. A specification written using staged allocation has a precise, formal semantics, and it can be executed directly inside a compiler. Specifications of nine standard C~calling conventions range in size from 15 to 30 lines each. An implementation of staged allocation takes about 250 lines of ML or 650~lines of C++. Each specification can be used not only to help a compiler implement the calling convention but also to generate a test suite.

We apply mathematical concept analysis in order to modularize legacy code.By analysing the relation between procedures and global variables, a so-called concept lattice is constructed.The paper explains how module structures show up in the lattice, and how the lattice can be used to assess cohesion and coupling between module candidates.Certain algebraic decompositions of the lattice can lead to automatic generation of modularization proposals.The method is applied to several examples written in Modula-2, Fortran, and Cobol; among them a >100kloc aerodynamics program.