我编译后，一个罐子抛出ClassNotFoundException

Question

I have 9 jar files in my project/lib folder and my classpath appears to be accurate. Everything works fine before I compile, but after compiling a single jar, stringtree-json-2.0.5.jar, throws ClassNotFoundException when I try to run it.

Things I've tried:

• Using '*' to load everything in my lib folder at once
• Switched from using Jackson (assuming it was jar specific), but Stringtree has the exact same problem. The offending jar is just a json parser that I just use once (in a pivotal area).
• Tried altering classpath before and after compile to insure it's correct.
• Probably a lot more I don't remember... been stuck on this for a week or so.

Here's the error as it's thrown:

org.bukkit.command.CommandException: Unhandled exception executing command 'rate' in plugin Pariah v1
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:189)
    at org.bukkit.craftbukkit.v1_5_R2.CraftServer.dispatchCommand(CraftServer.java:523)
    at net.minecraft.server.v1_5_R2.PlayerConnection.handleCommand(PlayerConnection.java:966)
    at net.minecraft.server.v1_5_R2.PlayerConnection.chat(PlayerConnection.java:884)
    at net.minecraft.server.v1_5_R2.PlayerConnection.a(PlayerConnection.java:841)
    at net.minecraft.server.v1_5_R2.Packet3Chat.handle(Packet3Chat.java:44)
    at net.minecraft.server.v1_5_R2.NetworkManager.b(NetworkManager.java:292)
    at net.minecraft.server.v1_5_R2.PlayerConnection.d(PlayerConnection.java:110)
    at net.minecraft.server.v1_5_R2.ServerConnection.b(SourceFile:35)
    at net.minecraft.server.v1_5_R2.DedicatedServerConnection.b(SourceFile:30)
    at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:580)
    at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:225)
    at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:476)
    at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:409)
    at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.NoClassDefFoundError: org/stringtree/json/JSONReader
    at pariah.AllMethods.ratingCall(AllMethods.java:351)
    at pariah.AllMethods.getPathRankRating(AllMethods.java:308)
    at pariah.Pariah.onCommand(Pariah.java:63)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
    ... 15 more
Caused by: java.lang.ClassNotFoundException: org.stringtree.json.JSONReader
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:80)
    at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
    ... 19 more

This is my current classpath:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry including="**/*.java" kind="src" output="target/classes" path="src">
        <attributes>
            <attribute name="optional" value="true"/>
            <attribute name="maven.pomderived" value="true"/>
        </attributes>
    </classpathentry>
    <classpathentry kind="src" output="target/test-classes" path="test">
        <attributes>
            <attribute name="optional" value="true"/>
            <attribute name="maven.pomderived" value="true"/>
        </attributes>
    </classpathentry>
    <classpathentry exported="true" kind="lib" path="lib/commons-codec-1.6.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/commons-logging-1.1.1.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/httpclient-4.2.2.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/httpclient-cache-4.2.2.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/httpcore-4.2.2.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/httpmime-4.2.2.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/stringtree-json-2.0.5.jar"/>
    <classpathentry exported="true" kind="lib" path="lib/bukkit-1.5.1-R0.1-20130325.184829-14.jar"/>
    <classpathentry kind="con" path="org.eclipse.jdt.junit.JUNIT_CONTAINER/4"/>
    <classpathentry exported="true" kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.6">
        <attributes>
            <attribute name="maven.pomderived" value="true"/>
        </attributes>
    </classpathentry>
    <classpathentry exported="true" kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
        <attributes>
            <attribute name="maven.pomderived" value="true"/>
        </attributes>
    </classpathentry>
    <classpathentry kind="output" path="target/classes"/>
</classpath>

I'm using eclipse to develop and compile. One oft repeated suggestion for solving this is to export the project as a Runnable Jar File. However, this is a plugin and so has no 'main' method.

Any other ideas out there? I feel I've exhausted (...myself and) all the options I've found on google and stackoverflow.

Thanks!

Answer 1

Just thinking around the transitive dependencies of the jar. Do you think you have the following class JSONReader in one of the jars. Generally using Jackson or any such frameworks, I have come across the transitive dependency of jars, jackson jar is dependent on other jars. Generally at compile time those transitive dependencies are not required but at the run time they are and we end facing NoClassDefFound error.

If that is the case, I would suggest to use maven for avoiding all such dependencies hassles.