we are members of the ZEST research group (Zurich Empirical Software
Engineering Team) based at the University of Zurich and the Delft
University of Technology. We are conducting an investigation on the
diffusion of innovations and we focus on the adoption of new language
features. Our research is focused on how API producers adapt their
interfaces to introduce support for Java 8’s lambdas. During the course
of our investigation, we manually inspected Been Validation’s source
code and documentation to understand whether Java’s lambdas have
widespread adoption. We would like to have your feedback on our
Our study focuses primarily on Functional Interfaces and Lambda
Expressions as these new features were introduced by the Java language
and adopted the Java JDK API, as they reduce implementation complexity,
improve readability, offer performance benefits and improve security
Our analysis showed that though BeenValidation 2.0 did not explicitly
introduce support for functional interfaces (e.g. by using the
@FunctionalInterface annotation). We noticed that the API does provide
compatibility with Java 8+ features, including lambda expressions (since
the API’s build platform is now on JDK 1.8). We would like to better
understand as to why no major change was necessitated to facilitate the
usage of lambda expressions with the API.
In most cases, developers choose to move to new releases to satisfy
particular dependency requirements, to take advantage of new Java
features (like streams and functional interfaces in the case of Java 8),
or just to standardize their implementation to align the API with the
Java JDK API. Can you provide us with more information about this?
How did you and your team tackle the choice to change the version of
Which factors did you take into account when doing this?
Are there any documented sources (e.g. Jira tickets, or issue tracker
issues) about that discussion you can provide us with?
Why were no explicit changes made to the interface to support lambda
Are there any future plans in place to make larger changes to the API
such that lambda expressions would be supported?
We thank you for taking the time to answer our questions. If you would
like to be posted about the results of this study, please let us know!
PhD Student - University of Zurich UZH
Department of Informatics
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