As per https://issues.apache.org/jira/browse/SPARK-2602 , this may be resolved for Java 6 with the java.awt.headless system property, which never hurt anyone running a command line app. I tested it and seemed to get rid of focus stealing.

Author: Sean Owen <srowen@gmail.com>

Closes #1747 from srowen/SPARK-2602 and squashes the following commits:

b141018 [Sean Owen] Set java.awt.headless during tests