attempting to downgrade to oracle jdk 9 because of stupid jdk 10 deprecation

.travis.yml

@@ -1,7 +1,7 @@
 language: java
 sudo: false
 jdk:
-- openjdk10
+- oraclejdk9
 cache:
   directories:
   - $HOME/.m2

main/pom.xml

@@ -317,9 +317,9 @@
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.8.0</version>
 				<configuration>
-					<source>10</source>
-					<target>10</target>
-					<release>10</release>
+					<source>9</source>
+					<target>9</target>
+					<release>9</release>
 					<annotationProcessorPaths>
 						<path>
 							<groupId>com.google.dagger</groupId>