Server App Engine Standard at localhost failed to start

问题

From eclipse, I created a Google App Engine Standard project and tried to Run it on local App Engine. It is not starting and throwing the below errors -

java.lang.NullPointerException
at java.base/java.util.concurrent.ConcurrentHashMap.putVal(ConcurrentHashMap.java:1011)
at java.base/java.util.concurrent.ConcurrentHashMap.put(ConcurrentHashMap.java:1006)
at java.base/java.util.Properties.put(Properties.java:1316)
at java.base/java.util.Collections$CheckedMap.put(Collections.java:3636)
at com.google.appengine.tools.development.SharedMain.setTimeZone(SharedMain.java:219)
at com.google.appengine.tools.development.SharedMain.postServerActions(SharedMain.java:188)
at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:398)
at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:45)
at com.google.appengine.tools.development.DevAppServerMain.run(DevAppServerMain.java:257)
at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:248)

Also note that I haven't made any changes to the project. It's the default that gets created.

回答1:

This is likely an issue with your jdk version. What does javac -version report back? I run into the same stack trace with version 12. Switching to 1.8 works.

On MacOS, this answer helps: How to set or change the default Java (JDK) version on OS X?

Other platforms should have similar ways to switch versions.

回答2:

This looks to be a JDK12 issue - it seems JDK12 is restricting the system properties exposed to programs, I've run into a similar issue with the OS version before.

I've reported it to Google, you can star it so they feel the weight of the matter: https://issuetracker.google.com/issues/140787205

来源：https://stackoverflow.com/questions/55694942/server-app-engine-standard-at-localhost-failed-to-start