Gradle task to dump classpath. Useful to launch external tools such as jshell. Using a gradle task/plugin to launch said tools breaks some key inputs such as tab completion because gradle forces its own input handling on top.

writeClasspath.gradle

task writeClasspath {
    doLast {
        Set pathSet = []
        project.tasks.withType(JavaExec) {
            pathSet.addAll(classpath.findAll { it.exists() })
        }
        project.subprojects.each {
            it.tasks.withType(JavaExec) {
                pathSet.addAll(classpath.findAll { it.exists() })
            }
        }
        // if (pathSet.isEmpty()) {
        //     List<String> classesPaths = project.sourceSets.main.output.getClassesDirs().collect { it.getPath() }
        //     jshellTask.logger.info(':jshell could not find the classpath, adding ' +
        //                            'the following paths from project sourceSets: {}', classesPaths)
        //     pathSet.addAll(classesPaths)
        //     List<String> depsPaths = project.configurations.compileClasspath.collect { it.getPath() }
        //     depsPaths.addAll(project.configurations.runtimeClasspath.collect { it.getPath() })
        //     jshellTask.logger.info(":jshell could not find the dependencies' classpath, adding " +
        //                            'the following paths from project configurations: {}', depsPaths)
        //     pathSet.addAll(depsPaths)
        // }
        // Exclude non-directory / non-jar files that jshell doesn't deal with
        pathSet = pathSet.findAll{ new File(it.toString()).isDirectory() || it.toString().endsWith('.jar') }

        def path = pathSet.join(System.getProperty("path.separator"))
        buildDir.mkdirs()
        new File(buildDir, "classpath.txt").text = path  + "\n"
    }
}