[jetty-dev] Investigation on the diffusion of innovation along with java

[FERNANDO PETRULIO <f.petrulio@xxxxxxxxxxxxxxxxx>]

Dear Developers,

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 Jetty’s source code and documentation to understand whether Java’s lambdas have widespread adoption. We would like to have your feedback on our findings.

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 contextualization.
Our analysis showed that though jetty 9.4 did not explicitly introduce support for functional interfaces (for 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 Java supported?
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 expressions?
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!

Kind Regards,
Fernando Petrulio.

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Fernando Petrulio Ph.D. Student University of Zurich UZH Department of Informatics