config: switch travis to openjdk8
config: switch travis to openjdk8

romani/checkstyle,romani/checkstyle,checkstyle/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,romani/checkstyle,rnveach/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,rnveach/checkstyle,romani/checkstyle,romani/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,romani/checkstyle,rnveach/checkstyle,checkstyle/checkstyle,checkstyle/checkstyle