【问题标题】：java.lang.NoClassDefFoundError: jdk/nashorn/api/scripting/NashornScriptEngineFactoryjava.lang.NoClassDefFoundError: jdk/nashorn/api/scripting/NashornScriptEngineFactory
【发布时间】：2021-02-26 06:02:54
【问题描述】：

我想在 1.16.3 中编写 Minecraft 模组。我已经在 1.12.2 中制作了一个 mod，但我没有这个问题。我只是下载 1.16.3 forge Mdk 并为 Eclipse 构建它（在 cmd 中使用“gradlew eclipse”）但是当我尝试运行 mod 时（使用“runClient.launch”）。它给出了一个错误：

java.lang.NoClassDefFoundError: jdk/nashorn/api/scripting/NashornScriptEngineFactory.

我尝试修改主文件和包以支持不必要的代码，但是当我开始时。它给了我同样的错误。

我的主文件：

package fr.luzog78.newmod;

import net.minecraft.block.Blocks;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.event.lifecycle.FMLClientSetupEvent;
import net.minecraftforge.fml.event.lifecycle.FMLCommonSetupEvent;
import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

@Mod("newmod")
public class NewMod {
    private static final Logger LOGGER = LogManager.getLogger();

    public NewMod() {
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::setup);
        FMLJavaModLoadingContext.get().getModEventBus().addListener(this::doClientStuff);

        MinecraftForge.EVENT_BUS.register(this);
    }

    private void setup(final FMLCommonSetupEvent event) {
        LOGGER.info("HELLO FROM PREINIT");
        LOGGER.info("DIRT BLOCK >> {}", Blocks.DIRT.getRegistryName());
    }

    private void doClientStuff(final FMLClientSetupEvent event) {
    }

//    @SubscribeEvent
//    public void onServerStarting(FMLServerStartingEvent event) {
//        // do something when the server starts
//        LOGGER.info("HELLO from server starting");
//    }
//
//    // You can use EventBusSubscriber to automatically subscribe events on the contained class (this is subscribing to the MOD
//    // Event bus for receiving Registry Events)
//    @Mod.EventBusSubscriber(bus=Mod.EventBusSubscriber.Bus.MOD)
//    public static class RegistryEvents {
//        @SubscribeEvent
//        public static void onBlocksRegistry(final RegistryEvent.Register<Block> blockRegistryEvent) {
//            // register a new block here
//            LOGGER.info("HELLO from Register Block");
//        }
//    }
}

还有堆栈跟踪：

Exception in thread "main" [13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]: java.lang.NoClassDefFoundError: jdk/nashorn/api/scripting/NashornScriptEngineFactory
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.coremod.CoreModEngine.loadCoreMod(CoreModEngine.java:48)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.coremod.CoreModProvider.addCoreMod(CoreModProvider.java:12)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:183)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:658)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:274)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:195)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:150)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:173)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:497)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.fml.loading.LoadingModList.addCoreMods(LoadingModList.java:85)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.fml.loading.moddiscovery.ModDiscoverer.discoverMods(ModDiscoverer.java:129)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.fml.loading.FMLLoader.beginModScan(FMLLoader.java:213)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.fml.loading.FMLServiceProvider.runScan(FMLServiceProvider.java:107)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at cpw.mods.modlauncher.TransformationServiceDecorator.runScan(TransformationServiceDecorator.java:114)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at cpw.mods.modlauncher.TransformationServicesHandler.lambda$runScanningTransformationServices$8(TransformationServicesHandler.java:115)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:271)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1766)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:484)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:474)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:913)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:578)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at cpw.mods.modlauncher.TransformationServicesHandler.runScanningTransformationServices(TransformationServicesHandler.java:116)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at cpw.mods.modlauncher.TransformationServicesHandler.initializeTransformationServices(TransformationServicesHandler.java:63)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at cpw.mods.modlauncher.Launcher.run(Launcher.java:76)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at cpw.mods.modlauncher.Launcher.main(Launcher.java:66)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1048]:   at net.minecraftforge.userdev.LaunchTesting.main(LaunchTesting.java:105)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1057]: Caused by: java.lang.ClassNotFoundException: jdk.nashorn.api.scripting.NashornScriptEngineFactory
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1057]:   at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:606)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1057]:   at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:168)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1057]:   at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
[13:16:47] [main/INFO] [STDERR/]: [java.lang.ThreadGroup:uncaughtException:1057]:   ... 33 more

【问题讨论】：

主要问题是编译器找不到类jdk/nashorn/api/scripting/NashornScriptEngineFactory。编译代码时（使用 javac 或诸如 ant 之类的构建管理工具？），您需要确保该类位于您的类路径中（可使用 -cp 配置）
您使用的是哪个 Java 版本？
@schetefan24 ，对不起，但我知道怎么做... x) srry
@JobyWilsonMathews java version "15.0.1" 2020-10-20 Java(TM) SE Runtime Environment (build 15.0.1+9-18) Java HotSpot(TM) 64-Bit Server VM (build 15.0.1+9-18, mixed mode, sharing) 但我已经用 java 8 测试过

标签： java eclipse noclassdeffounderror minecraft-forge mod

【解决方案1】：

您使用的 Minecraft 代码似乎取决于 Nashorn 脚本引擎。 Nashorn 在 Java 15 中是 removed from the JDK，您似乎正在运行它。

降级到 JDK 14 或更早版本。

【讨论】：

OOOOhhhh 非常感谢您！这样可行！！谢谢，我确定我已经完成了，但是.. 没有 xD 谢谢！！！
但现在我有 "java.lang.UnsupportedClassVersionError" x)
不好...我忘记修改路径但仅适用于 jdk1.8
为什么会被删除？我已经可以看到这个问题和答案在未来几年将如何获得成千上万的浏览量......
@Akito：上面的链接没有说明吗？

【解决方案2】：

解决方案

Nashorn 已从 Java 15 中的 JDK 中删除 (https://openjdk.java.net/jeps/372)
您需要使用 Java 1.8 启动（以避免 UnsupportedClassVersionError）
所以你必须：
1. 转到 Project Properties >> Java compiler >> Compiler >> compilance level 并修改为 Java SE - 1.8
2. 修改你的路径（放jdk1.8）
3. 如果这不起作用，请转到 Preferences >> Java >> Installed JREs 和 Preferences >> Java >> Installed JREs >> Execution Environments

感谢@LukeWoodward ！！

【讨论】：