我有一个eclipse项目，我使用Ant构建将其导出到可运行的jar中，并且使用jar-in-jar加载器将一些jar库放入项目jar中。这曾经奏效，而我记得，更新到Java 9才是破坏它的原因。我可能是错的，但我只是在使用罐子一段时间，直到罐子停止工作。

在eclipse中运行项目效果很好，但是当我使用jar并从其中一个库中调用方法时，我得到了NoClassDefFoundError。不管哪个库。

java.lang.NoClassDefFoundError: myutils/MyUtils
        at packagename.Utils.input(Utils.java:42)
        at packagename.Main.main(Main.java:83)
        at java.base/jdk.internal.reflect.NativeMethodaccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodaccessorImpl.invoke(NativeMethodaccessorImpl.java:62)
        at java.base/jdk.internal.reflect.DelegatingMethodaccessorImpl.invoke(DelegatingMethodaccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:567)
        at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoader.java:58)
Caused by: java.lang.ClassnotFoundException: myutils.MyUtils
        at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:436)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:588)
        at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
        ... 7 more

这是Ant版本：

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<project default="create_run_jar" name="Create Runnable Jar for Project ProjectName with Jar-in-Jar Loader">
    <!--this file was created by eclipse Runnable JAR file Export Wizard-->
    <!--ANT 1.7 is required-->
    <!--define folder properties-->
    <property name="dir.buildfile" value="."/>
    <property name="dir.workspace" value="${dir.buildfile}/.."/>
    <property name="dir.libraries" value="${dir.buildfile}/../../libraries"/>
    <property name="dir.projectjars" value="${dir.buildfile}/../../project-jars"/>
    <target name="create_run_jar">
        <jar destfile="${dir.projectjars}/jarname.jar">
            <manifest>
                <attribute name="Main-Class" value="org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader"/>
                <attribute name="Rsrc-Main-Class" value="packagename.Main"/>
                <attribute name="Class-Path" value="."/>
                <attribute name="Rsrc-Class-Path" value="./ guava-19.0.jar jsoup-1.9.1.jar myutils.jar"/>
            </manifest>
            <zipfileset src="jar-in-jar-loader.zip"/>
            <fileset dir="${dir.buildfile}/bin"/>
            <zipfileset dir="${dir.libraries}" includes="guava-19.0.jar"/>
            <zipfileset dir="${dir.libraries}" includes="jsoup-1.9.1.jar"/>
            <zipfileset dir="${dir.projectjars}" includes="myutils.jar"/>
        </jar>
    </target>
</project>

编辑：这是MANIFEST.MF：

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.10.5
Created-By: 12.0.2+10 (Oracle Corporation)
Main-Class: org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader
Rsrc-Main-Class: packagename.Main
Rsrc-Class-Path: ./ guava-19.0.jar jsoup-1.9.1.jar myutils.jar
Class-Path: .