ESC/Java: Difference between revisions

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'''ESC/Java''' (and more recently '''ESC/Java2'''), the "Extended Static Checker for Java," is a [[programming tool]] that attempts to find common [[run-time error]]s in [[Java (programming language)|Java]] programs at [[compile time]].<ref>{{cite conference |last1=Flanagan |first1=C. |last2=Leino |first2=K.R.M. |last3=Lillibridge |first3=M. |last4=Nelson |first4=G. |last5=Saxe |first6=J. B. |last6=Stata |first5=R. |title=Extended static checking for Java |work=Proceedings of the Conference on Programming Language Design and Implementation |pages=234–245 |year=2002 |isbn=1-58113-463-0 |doi=10.1145/512529.512558}}</ref> The underlying approach used in ESC/Java is referred to as [[extended static checking]], which is a collective name referring to a range of techniques for [[static code analysis|statically checking]] the correctness of various program constraints. For example, that an integer variable is greater-than-zero, or lies between the [[bounds checking|bounds of an array]]. This technique was pioneered in ESC/Java (and its predecessor, ESC/Modula-3) and can be thought of as an extended form of [[type checking]]. Extended static checking usually involves the use of an [[automated theorem proving|automated theorem prover]] and, in ESC/Java, the Simplify theorem prover was used.

ESC/Java is neither [[soundness|sound]] nor [[completeness (logic)|complete]]. This was intentional and aims to reduce the number of errors and/or warnings reported to the programmer, in order to make the tool more useful in practice. However, it does mean that: firstly, there are programs that ESC/Java will erroneously consider to be incorrect (known as ''false-positives''); secondly, there are incorrect programs it will consider to be correct (known as ''false-negatives''). Examples in the latter category include errors arising from [[modular arithmetic]] and/or [[Thread (computer science)|multithreading]].

ESC/Java was originally developed at the [[DEC Systems Research Center|Compaq Systems Research Center]] (SRC). SRC launched the project in 1997, after work on their original extended static checker, ESC/Modula-3, ended in 1996. In 2002, SRC released the [[source code]] for ESC/Java and related tools. Recent versions of ESC/Java are based around the [[Java Modeling Language]] (JML). Users can control the amount and kinds of checking by annotating their programs with specially formatted comments or ''[[Directive (programming)|pragmas]]''.