Does the Introduction of Lambda Expressions Improve the Comprehension of Java Programs?

Lucas, Walter; Bonifácio, Rodrigo; Canedo, Edna Dias; Marcílio, Diego; Lima, Fernanda

doi:10.1145/3350768.3350791

Cited by 27 publications

(20 citation statements)

References 19 publications

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“…AP2 : Avoid "bridging" between stream API and legacy collection APIs. Using a long λ-expression in a single map() operation may make stream code less "functional," more difficult to read [29], and less amenable to parallelism. Consider the abbreviated commit below that returns the occupied drive letters on Windows systems by collecting the first uppercase character of the path: The λ-expression has been replaced with method references, however, there are more subtle yet import changes.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

An Empirical Study on the Use and Misuse of Java 8 Streams

Khatchadourian

Tang

Bagherzadeh

et al. 2020

Lecture Notes in Computer Science

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Streaming APIs allow for big data processing of native data structures by providing MapReduce-like operations over these structures. However, unlike traditional big data systems, these data structures typically reside in shared memory accessed by multiple cores. Although popular, this emerging hybrid paradigm opens the door to possibly detrimental behavior, such as thread contention and bugs related to non-execution and non-determinism. This study explores the use and misuse of a popular streaming API, namely, Java 8 Streams. The focus is on how developers decide whether or not to run these operations sequentially or in parallel and bugs both specific and tangential to this paradigm. Our study involved analyzing 34 Java projects and 5.53 million lines of code, along with 719 manually examined code patches. Various automated, including interprocedural static analysis, and manual methodologies were employed. The results indicate that streams are pervasive, parallelization is not widely used, and performance is a crosscutting concern that accounted for the majority of fixes. We also present coincidences that both confirm and contradict the results of related studies. The study advances our understanding of streams, as well as benefits practitioners, programming language and API designers, tool developers, and educators alike.

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Section: Resultsmentioning

confidence: 99%

“…Previous studies [29,32,36,46,51] have focused specifically on λ-expressions. While λ-expressions are used as arguments to stream operations, our focus is on stream operations themselves.…”

Section: Related Workmentioning

confidence: 99%

An Empirical Study on the Use and Misuse of Java 8 Streams

Khatchadourian

Tang

Bagherzadeh

et al. 2020

Lecture Notes in Computer Science

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“…In the first phase, whose results we presented in previ ous work (Lucas et al, 2019), we carried out a quantitative assessment of 66 pairs of code snippets, using stateofthe art models for measuring software comprehension (see Sec tion 3.2). Each pair corresponds to a method body before and after introducing lambda expressions.…”

Section: Study Settingsmentioning

confidence: 99%

“…In previous work (Lucas et al, 2019), we investigated how the introduction of lambda expressions impacts source code comprehension. We found that stateoftheart metrics to measure code readability fail to capture the benefits of intro ducing lambda expressions.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Impact of Introducing Lambda Expressions in Java Programs

Mendonça

Fortes

Lopes

et al. 2020

JSERD

Self Cite

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Background: The Java programming language version eight introduced several features that encourage the functional style of programming, including the support for lambda expressions and the Stream API. Currently, there is common wisdom that refactoring legacy code to introduce lambda expressions, besides other potential benefits, simplifies the code and improves program comprehension. Aims: The purpose of this work is to investigate this belief, conducting an in-depth study to evaluate the effect of introducing lambda expressions on program comprehension. Method: We conduct this research using a mixed-method study. For the quantitative method, we quantitatively analyze 166 pairs of code snippets extracted directly either from GitHub or from recommendations from three tools (RJTL, NetBeans, and IntelliJ). We also surveyed practitioners to collect their perceptions about the benefits on program comprehension when introducing lambda expressions. We asked practitioners to evaluate and rate sets of pairs of code snippets. Results: We found contradictory results in our research. Based on the quantitative assessment, we could not find evidence that the introduction of lambda expressions improves software readability—one of the components of program comprehension. Our results suggest that the transformations recommended by the aforementioned tools decrease program comprehension when assessed by two state-of-the-art models to estimate readability. Differently, our findings of the qualitative assessment suggest that the introduction of lambda expression improves program comprehension in three scenarios: when we convert anonymous inner classes to a lambda expression, structural loops with inner conditional to a anyMatch operator, and structural loops to filter operator combined with a collect method. Implications: We argue in this paper that one can improve program comprehension when she applies particular transformations to introduce lambda expressions (e.g., replacing anonymous inner classes with lambda expressions). Also, the opinion of the participants shines the opportunities in which a transformation for introducing lambda might be advantageous. This might support the implementation of effective tools for automatic program transformations.

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“…They find that there is an increasing trend of lambda usage and the main reason behind this is the increased maintainability of the code. Lucas et al (2019) investigate the usage of the Java streams API in conjunction with lambda expressions to better understand how the code's maintainability is affected.…”

Section: Introductionmentioning

confidence: 99%

The indolent lambdification of Java

2021

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As Java 8 introduced functional interfaces and lambda expressions to the Java programming language, the JDK API was changed to introduce support for lambda expressions, thus allowing consumers to define lambda functions when using Java’s collections. While the JDK API allows for a functional paradigm, for API consumers to be able to completely embrace Java’s new functional features, third-party APIs must also support lambda expressions. To understand the current state of the Java ecosystem, we investigate (i) the extent to which third-party Java APIs have changed their interfaces, (ii) why or why not they introduce functional interface support and (iii) in the case the API has changed its interface how it does so. We also investigate the consumers’ perspective, particularly their ease in using lambda expressions in Java with APIs. We perform our investigation by manually analyzing the top 50 popular Java APIs, conducting in-person and email interviews with 23 API producers, and surveying 110 developers. We find that only a minority of the top 50 APIs support functional interfaces, the rest does not support them, predominantly in the interest of backward compatibility. Java 7 support is still greatly desirable due to enterprise projects not migrating to newer versions of Java. This suggests that the Java ecosystem is stagnant and that the introduction of new language features will not be enough to save it from the advent of new languages such as Kotlin (JVM based) and Rust (non-JVM based).

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Does the Introduction of Lambda Expressions Improve the Comprehension of Java Programs?

Cited by 27 publications

References 19 publications

An Empirical Study on the Use and Misuse of Java 8 Streams

An Empirical Study on the Use and Misuse of Java 8 Streams

Understanding the Impact of Introducing Lambda Expressions in Java Programs

The indolent lambdification of Java

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