Update Travis build.
diff --git a/.travis.yml b/.travis.yml
index 33dac6f..66fb005 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -17,9 +17,9 @@
 sudo: false

 

 jdk:

-  - openjdk7

-  - oraclejdk7

-  - oraclejdk8

+  - openjdk8

+  - openjdk11

+  - openjdk15

 

 after_success:

   - mvn -V clean cobertura:cobertura coveralls:report --no-transfer-progress