Gradle plugin which uses itself

build.gradle

// Let's say we have a gradle plugin. Now we want that gradle plugin project to actually use the exact plugin.
// There are probably multiple ways we can bootstrap this. One way is to build the jar, and use that, but that's boring.
// Here we show how we can have the plugin-project use the actual plugin we are building.

// :: We load the groovy script on runtime, only then are we able to apply the plugin
// Setup the groovy classpath. Start with our own files
def classpaths = [file('src/main/groovy').absolutePath, file('src/main/resources').absolutePath]
// The groovy script engine wants a string array
String[] classpathArray = classpaths.toArray(new String[classpaths.size()]);
// Start a groovy script engine with our classpaths
def engine = new GroovyScriptEngine(classpathArray, this.getClass().getClassLoader())
// Now we can load the plugin script
def pluginClass = engine.loadScriptByName('org/example/MyPlugin.groovy')

apply plugin: pluginClass

org.example MyPlugin.groovy

class MyPlugin implements Plugin<Project> {

    @Override
    void apply(Project project) {
        // Here you do whatever you normally want in your plugin
    }
}