To build java sdk 0.7, is JDK 1.7 OK or have to use JDK 1.8?

Questions
1

To build okta java sdk 0.7, is JDK 1.7 enough or have to use JDK 1.8?

2

Prereqs are here: https://github.com/okta/okta-sdk-java/wiki/Release-Guide