An experiment was conducted to compare programmer productivity and defect rates for Java and C++. A modified version of the Personal Software Process (PSP) was used to gather defect rate, bug rate, and productivity data on C++ and Java during two real world development projects. A bug is defined to be a problem detected during testing or deployment. A defect is either a bug, or an error detected during compile time. A typical C++ program had two to three times as many bugs per line of code as a typical Java program. C++ also generated between 15 per cent and 50 per cent more defects per line, and perhaps took six times as long to debug. Java was between 30 per cent and 200 per cent more productive, in terms of lines of code per minute. When defects were measured against development time, Java and C++ showed no difference, but C++ had two to three times as many bugs per hour. Statistics were generated using Student's t-test at a 95 per cent confidence level. Some discussion of why the differences occurred is included, but the reasons offered have not been tested experimentally. The study is limited to one programmer over two projects, so it is not a definitive experimental result. The programmer was experienced in C++, but only learning Java, so the results would probably favour Java more strongly for equally-experienced programmers. The experiment shows that it is possible to experimentally measure the fitness of a programming language. Copyright © 1999 John Wiley & Sons, Ltd.

We describe the design and implementation of the Glue-Nail database system. The Nail language is a purely declarative query language; Glue is a procedural language used for non-query activities. The two languages combined are sufficient to write a complete application. Nail and Glue code both compile into the target language IGlue. The Nail compiler uses variants of the magic sets algorithm, and supports well-founded models. Static optimization is performed by the Glue compiler using techniques that include peephole methods and data flow analysis. The IGlue code is executed by the IGlue interpreter, which features a run-time adaptive optimizer. The three optimizers each deal with separate optimization domains, and experiments indicate that an effective synergism is achieved. The Glue-Nail system is largely complete and has been tested using a suite of representative applications.