diff --git a/.travis.yml b/.travis.yml
index aa15eea..7ea9aee 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -36,12 +36,17 @@
   - ./gradlew check :grpc-all:jacocoTestReport
 
 after_success:
-  - if \[ "$TRAVIS_OS_NAME" = linux \]; then ./gradlew :grpc-all:coveralls; fi
+    # Upload to coveralls once, instead of for each job in the matrix
+  - if \[\[ "$TRAVIS_JOB_NUMBER" == *.1 \]\]; then ./gradlew :grpc-all:coveralls; fi
   - bash <(curl -s https://codecov.io/bash)
 
 os:
   - linux
 
+jdk:
+  - oraclejdk8
+  - oraclejdk9
+
 notifications:
   email: false