A utility to perform a best effort selection of the Java version needed by the build tool to build a Java project. Moderne offers a large public dataset of type attributed abstract syntax trees (ASTs) produced from OSS code. These ASTs are built daily. In order to produce an AST, the Java version that the project's build tool must run with must be known in advance.
Unfortunately, neither Gradle or Maven require any explicit signal about the Java version they require, so this must be inferred from the project using a variety of heuristics.
| Heuristic | Notes |
|---|---|
Gradle sourceCompatibility |
See Java Plugin reference |
Maven maven.compiler.source |
See blog |
| Use of libraries requiring a minimum Java 11 version | Caffeine 3.+. This would likely involve looking for direct dependencies, since otherwise chicken and egg problem. |
| References to base docker images | e.g. openjdk:11-jdk-slim |
| CircleCI Java version | See openjdk. Also check docs for what implied default version is |
| TravisCI Java version | See Building a Java project |
| GitHub actions Java version | See GitHub actions docs |
| Any reference to Jigsaw | The presence of a module-info.java or a declared dependency on a module |
| References to JakartaEE | ?? |
| sdkman config | See this example |
| jenv config | .java-version |