What Java version does our 10.x+ SDK/J platform run?

The complete version of Java that is running on the 10.x to 11.x platform is:  JavaVM version is 1.6.0_21 (6u21)

You can see patches up to 6u21 in the following page:  http://www.oracle.com/technetwork/jp/java/javase/releasenotes-136954.html