hey, I find there are some issue for travis with openjdk11, see [1][2]
According to this thread[3], looks like we need switch to xenial. I try with PR #3948. But it works for openjdk11, the travis build fail with oraclejdk8[5]. so I think we have two options here 1. remove oaclejdk8 in travis build 2. write specific script to fix this issue. for exmaple [6] Any thoughts? 1:https://travis-ci.org/apache/incubator-dubbo/builds/525794804 2:https://travis-ci.org/apache/incubator-dubbo/builds/525556607 3:https://travis-ci.community/t/install-of-openjdk11-is-failing-again/3061/15 4:https://github.com/apache/incubator-dubbo/pull/3948 5:https://github.com/travis-ci/travis-ci/issues/10290 6:https://github.com/typelevel/jawn/pull/134/files
