What is the minimum JDK for Gradle plugins?

This question arises from a discussion on Twitter:

What is the minimum JDK that needs to be supported when writing a Gradle plugin?

Following on from that:

Would this differ between Gradle 1. and 2.x?

I think it would be good if the Gradle team can provide a recommendation. Even maybe supply an API call similar to gradleApi() which can be used to set it.

Gradle 1.x supports Java 5, Gradle 2.x supports Java 6.

The best thing to do is to compile with the minimum version that Gradle supports if you want all Gradle users to be able to use it.

We are working on some tooling for plugin developers that will help with this kind of thing.