Switched to Java 13.

.circleci/config.yml

@@ -30,11 +30,11 @@ defaults_gradle: &defaults_gradle
         path: build/reports/
 
 jobs:
-  build_gradle_jdk12:
+  build_gradle_jdk13:
     <<: *defaults
 
     docker:
-      - image: openjdk:12-jdk
+      - image: openjdk:13-jdk
 
     <<: *defaults_gradle
 
@@ -51,5 +51,5 @@ workflows:
   gradle:
         jobs:
         - build_gradle_jdk8
-        - build_gradle_jdk12
+        - build_gradle_jdk13
 

.idea/misc.xml

@@ -6,7 +6,7 @@
     <list size="0" />
   </component>
   <component name="ExternalStorageConfigurationManager" enabled="true" />
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_12" project-jdk-name="12" project-jdk-type="JavaSDK" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_12" project-jdk-name="13" project-jdk-type="JavaSDK" />
   <component name="SuppressionsComponent">
     <option name="suppComments" value="[]" />
   </component>

.travis.yml

@@ -14,7 +14,7 @@ addons:
 
 jdk:
   - oraclejdk8
-  - openjdk12
+  - openjdk13
 
 before_install:
   - chmod +x gradlew