How to enforce a java compiler version with gradle?

Question

In all of my projects, I use gradle and specify the following:

sourceCompatibility = "1.7"; // for example
targetCompatibility = "1.7"; // defaults to sourceCompatibility

Now, I have three different versions of the JDK installed, from 1.6 to 1.8. In order to switch from one version to another, I source shell files to change PATH, JAVA_HOME and even JDK_HOME.

By accident it can happen that I use the wrong JDK version and I don't want that... Is there a possibility to check that the compiler version is equal to targetCompatibility before attempting any compilation task?

Answer 1

I use the following:

task checkJavaVersion << {
    if (!JavaVersion.current().isJava6()) {
        String message = "ERROR: Java 1.6 required but " +
                          JavaVersion.current() +
                          " found. Change your JAVA_HOME environment variable.";
        throw new IllegalStateException(message);
    }
}

compileJava.dependsOn checkJavaVersion