UnsupportedClassVersionError

报告没有提到任何仓库文件或测试。先复现 firebase setup:emulators:firestore 和 firebase serve --only firestore 命令，然后检查 Firestore 模拟器是如何启动的，以及它需要哪个 Java 运行时。模拟器能够在不出现 UnsupportedClassVersionError 的情况下启动，即表示完成。

Running the emulator after firebase setup:emulators:firestore gives the following error:

firebase serve --only firestore                                                                
✔  firestore: started on http://localhost:8080
⚠  firestore: Exception in thread "main"
⚠  firestore: java.lang.UnsupportedClassVersionError: com/google/cloud/datastore/emulator/firestore/CloudFirestore : Unsupported major.minor version 52.0
        at java.lang.ClassLoader.defineClass1(Native Method)
        at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
        at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
        at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
⚠  firestore:
        at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
        at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
⚠  firestore:
        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
        at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
⚠  firestore:


Error: firestore: emulator has exited with code: 1