A Survey of the Forms of Java Reference Names

The readability of identifiers is a major factor of program comprehension and an aim of naming convention guidelines. Due to their semantic content, identifiers are also used in feature and bug location, among other software maintenance tasks. Looking at how names are used in practice may lead to insights on potential problems for comprehension and for programming support tools that process identifiers. Class and method names are already well represented in the literature. This paper presents an investigation of Java field, formal argument and local variable names, which we collectively call reference names. These names cannot be ignored because they constitute over half the unique names and almost 70% of the name declarations in the corpus investigated. We analysed the forms of 3.5 million reference name declarations in 60 well known Java projects, examining the phrasal structure of names composed of known words and acronyms. The structures found in practice were evaluated against those given in the literature. The use of unknown abbreviations and words, which may pose a problem for program comprehension, was also identified. Based on our observations of the rich diversity of reference names, we suggest issues to be taken into account for future academic research and for improving tools that rely on names as sources of information.