Windows 10 改java版本？

Question

Im working with Intellij IDEA + JDK 14 and want to execute my project as jar in my console. Herefor I use

java -jar pathToJar

There is always the following Error message:

Exception in thread "main" java.lang.UnsupportedClassVersionError: de/marco/api/Main has been compiled by a more recent version of the Java Runtime (class file version 58.0), this version of the Java 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 know what this error message means, but I dont know how to fix. I´ve set already in my system under "PATH" the path to my JDK. My computer uses Java 8 :

C:\Users\User>java -version
java version "1.8.0_261"
Java(TM) SE Runtime Environment (build 1.8.0_261-b12)
Java HotSpot(TM) Client VM (build 25.261-b12, mixed mode)

Could anyone help me how to change the Java version of my Computer, that i could use a newer version for my compiler. Thanks a lot

Answer 1

It is very simple:

• either you tell IntelliJ to compile your classes to java 8 bytecode
• or you ensure that your windows command line is pointing to your java 11 setup

For Intellij; you look into "Project Settings", then turn to "SDKs" under Platform Settings. You could point that to a JDK8 installation.

Alternatively, as you probably installed Java 14 on purpose: locate where it sits on your disk, and ensure your Windows PATH variable points to that location. Or just put some "wrapper" script somewhere into your PATH, and have that wrapper script call the "java 14" java.

Answer 2

you wrote the program and compiled it using a higher version of jdk than you used to execute it. Just go to build settings and set the compiler compliance level to the jdk you are using. If you want to use JDK 14 instead of 8, just uninstall jdk 8 and java will use jdk14. I hope this helped:)

Answer 3

You program didn't work because your computer points to an old version of java JDK in PATH. You can just uninstall Java 8 and reinstall java 14. In cases, if don't want to delete the old one or you have manually changed the PATH variable, then:

Step 1: Delete old items of Java JDK from PATH.

Type "this pc" in the search bar next to the start button -> Right click "This PC", choose "Properties" -> click "Advanced system settings" on the left side bar -> click "Advanced" tab -> click "Environment Variables" button at bottom -> Modify the "Path" variable under System variables panel and DELETE all your old java path information(or any item in other variables with your old java information). If you done right, java -version should not work right now.

Step 2: install Java JDK 14 from installer

New Java PATH info will be automatically added to the PATH environment variable. You don't need to manually update anything. (If you do want, follow step 1 to change PATH)