I can run MC 1.18.1 + Optifine perfetctly early on. But after I installed Forge 39.0.18 on my client and ran again, I got an error message about log4j below, then I found out that Forge 39.0.18 is using log4j 2.15.0 downloaded by Forge itself.
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/logging/log4j/core/lookup/StrLookup
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.LoggerContext.<clinit>(LoggerContext.java:85)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.createContext(ClassLoaderContextSelector.java:254)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.locateContext(ClassLoaderContextSelector.java:218)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:136)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:123)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.selector.ClassLoaderContextSelector.getContext(ClassLoaderContextSelector.java:117)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:150)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:47)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.LogManager.getContext(LogManager.java:196)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.LogManager.getLogger(LogManager.java:599)
at MC-BOOTSTRAP/
[email protected]/org.apache.logging.log4j.LogManager.getLogger(LogManager.java:585)
at MC-BOOTSTRAP/
[email protected]/cpw.mods.modlauncher.Launcher.main(Launcher.java:76)
at MC-BOOTSTRAP/
[email protected]/cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26)
at MC-BOOTSTRAP/
[email protected]/cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23)
at
[email protected]/cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:90)
Caused by: java.lang.ClassNotFoundException: org.apache.logging.log4j.core.lookup.StrLookup
at
[email protected]/cpw.mods.cl.ModuleClassLoader.loadClass(ModuleClassLoader.java:135)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520)
... 15 more
