remove travis jdk
diff --git a/.travis.yml b/.travis.yml
index 1790f51..abec7f9 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,8 +3,6 @@
 
 jdk:
     - openjdk11
-    - openjdk10
-    - openjdk9
     - openjdk8
    #   - openjdk7