Fix Java travis tests.
diff --git a/travis.sh b/travis.sh
index 317bef4..b9ff09b 100755
--- a/travis.sh
+++ b/travis.sh
@@ -100,7 +100,9 @@
 build_java() {
   # Java build needs `protoc`.
   internal_build_cpp
-  cd java && mvn test && cd util && mvn test && mvn assembly:single && cd ../..
+  cd java && mvn test && mvn install
+  cd util && mvn test && mvn assembly:single
+  cd ../..
   cd conformance && make test_java && cd ..
 }