使用 JDK 13 编译并使用 JRE 8 运行

Question

I compiled my program, but when i try to run it, i get this error :

Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.UnsupportedClassVersionError: Lanceur has been compiled by a more recent version of the Java Runtime (class file version 57.0), this version of the J    ava Runtime only recognizes class file versions up to 52.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.access$100(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)

I tried to "move" the JDK 13 all the way up in PATH, restarted my PC, but nothing changed. Here is a screenshot :

I then tried to download JRE 13, but can't find it anywhere.

How can i do this ? I can't update to JDK 14 or up, because i need something that was removed in these versions

Answer 1

As you're compiling without a build environment, you'll need to build with:

javac -target 1.8 -source 1.8 MainClass.java

Java versioning is confusing but stick with 13 until you get used to it.