java.lang.IllegalArgumentException: Class file is Java 8 but max supported is Java 7

[adiantek]

Is there any way to fix it without downgrade to Java 7?

Unable to update:
java.lang.IllegalArgumentException: Class file is Java 8 but max supported is Java 7: myclassfile
at com.google.appengine.tools.admin.Application.checkJavaVersion(Application.java:1378)
at com.google.appengine.tools.admin.Application.checkJavaClassVersion(Application.java:1347)
at com.google.appengine.tools.admin.Application.checkJavaVersion(Application.java:1329)
at com.google.appengine.tools.admin.Application.copyOrLinkFile(Application.java:1256)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1235)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1222)
at com.google.appengine.tools.admin.Application.populateStagingDirectory(Application.java:756)
at com.google.appengine.tools.admin.Application.createStagingDirectory(Application.java:708)
at com.google.appengine.tools.admin.AppAdminImpl.doUpdate(AppAdminImpl.java:570)
at com.google.appengine.tools.admin.AppAdminImpl.update(AppAdminImpl.java:57)
at com.google.appengine.tools.admin.AppCfg$UpdateAction.execute(AppCfg.java:1490)
at com.google.appengine.tools.admin.AppCfg.executeAction(AppCfg.java:357)
at com.google.appengine.tools.admin.AppCfg.(AppCfg.java:218)
at com.google.appengine.tools.admin.AppCfg.(AppCfg.java:119)
at com.google.appengine.tools.admin.AppCfg.main(AppCfg.java:115)
com.google.appengine.tools.admin.AdminException: Unable to update app: Class file is Java 8 but max supported is Java 7: myclassfile
at com.google.appengine.tools.admin.AppAdminImpl.doUpdate(AppAdminImpl.java:578)
at com.google.appengine.tools.admin.AppAdminImpl.update(AppAdminImpl.java:57)
at com.google.appengine.tools.admin.AppCfg$UpdateAction.execute(AppCfg.java:1490)
at com.google.appengine.tools.admin.AppCfg.executeAction(AppCfg.java:357)
at com.google.appengine.tools.admin.AppCfg.(AppCfg.java:218)
at com.google.appengine.tools.admin.AppCfg.(AppCfg.java:119)
at com.google.appengine.tools.admin.AppCfg.main(AppCfg.java:115)
Caused by: java.lang.IllegalArgumentException: Class file is Java 8 but max supported is Java 7: myclassfile
at com.google.appengine.tools.admin.Application.checkJavaVersion(Application.java:1378)
at com.google.appengine.tools.admin.Application.checkJavaClassVersion(Application.java:1347)
at com.google.appengine.tools.admin.Application.checkJavaVersion(Application.java:1329)
at com.google.appengine.tools.admin.Application.copyOrLinkFile(Application.java:1256)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1235)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1224)
at com.google.appengine.tools.admin.Application.copyOrLink(Application.java:1222)
at com.google.appengine.tools.admin.Application.populateStagingDirectory(Application.java:756)
at com.google.appengine.tools.admin.Application.createStagingDirectory(Application.java:708)
at com.google.appengine.tools.admin.AppAdminImpl.doUpdate(AppAdminImpl.java:570)
... 6 more

And from maven:
[INFO] GCLOUD: Reading application configuration data...
[INFO] GCLOUD:
[INFO] GCLOUD:
[INFO] GCLOUD: Beginning interaction for module default...
[INFO] GCLOUD: Unable to stage app: Class file is Java 8 but max supported is Java 7: myapp/DemoServlet.class in /home/xxx/src/xxx/target/appengine-try-java-1.0/WEB-INF/lib/appengine-try-java-1.0.jar

[patflynn]

java 8 is not available in App Engine Standard at the moment. There is an alpha which you could try signing up to.

Otherwise you'll have to wait for the public Beta.

[loosebazooka]

In gradle you should be able to set the target version of your module to java7 so it creates java7 output.

see sourceCompatability and targetCompatability in https://docs.gradle.org/current/userguide/java_plugin.html

[adiantek]

@loosebazooka I wrote: "without downgrade to Java 7". Thanks @patflynn, I will fill it tomorrow.

[loosebazooka]

Oh whoops, sometimes people have the same problem because they want to build with java8.