请检查你的代码是否由两个具有相同类名和包定义的模块项目组成。例如，如果有人使用复制粘贴来创建基于先前实现的接口的新实现，就会发生这种情况。

In my case, I ran into this error this way. pom.xml of my project defined two dependencies A and B. And both A and B defined dependency on same artifact (call it C) but different versions of it (C.1 and C.2). When this happens, for each class in C maven can only select one version of the class from the two versions (while building an uber-jar). It will select the "nearest" version based on its dependency mediation rules and will output a warning "We have a duplicate class..." If a method/class signature changes between the versions, it can cause a java.lang.IncompatibleClassChangeError exception if the incorrect version is used at runtime.

高级:如果A必须使用C的v1, B必须使用C的v2，那么我们必须在A和B的poms中重新定位C，以避免类冲突(我们有一个重复类警告)，当构建依赖于A和B的最终项目时。

请检查你的代码是否由两个具有相同类名和包定义的模块项目组成。例如，如果有人使用复制粘贴来创建基于先前实现的接口的新实现，就会发生这种情况。

While these answers are all correct, resolving the problem is often more difficult. It's generally the result of two mildly different versions of the same dependency on the classpath, and is almost always caused by either a different superclass than was originally compiled against being on the classpath or some import of the transitive closure being different, but generally at class instantiation and constructor invocation. (After successful class loading and ctor invocation, you'll get NoSuchMethodException or whatnot.)

如果这种行为看起来是随机的，那么它很可能是多线程程序类根据最先遇到的代码加载不同的传递依赖项的结果。

要解决这些问题，请尝试使用-verbose作为参数启动VM，然后查看异常发生时正在加载的类。你应该会看到一些令人惊讶的信息。例如，拥有相同依赖项的多个副本，以及您从未预料到的版本，或者如果您知道它们被包括在内，您就不会接受这些版本。

用Maven解决重复的jar最好是结合Maven下的Maven - Dependency - Plugin和Maven -enforcer- Plugin(或SBT的Dependency Graph Plugin)，然后将这些jar添加到顶级POM的一部分或作为SBT中的导入依赖元素(以删除这些依赖)。

好运！

在浪费了太多时间后记录下另一个场景。

确保您的依赖jar中没有包含带有EJB注释的类。

我们有一个普通的jar文件，它有一个@local注释。这个类后来从这个公共项目移到我们的主ejb jar项目中。ejb jar和公共jar都捆绑在ear中。我们的公共jar依赖项的版本没有更新。因此，两个类试图成为具有不兼容的更改的东西。

I have also discovered that, when using JNI, invoking a Java method from C++, if you pass parameters to the invoked Java method in the wrong order, you will get this error when you attempt to use the parameters inside the called method (because they won't be the right type). I was initially taken aback that JNI does not do this checking for you as part of the class signature checking when you invoke the method, but I assume they don't do this kind of checking because you may be passing polymorphic parameters and they have to assume you know what you are doing.

示例c++ JNI代码:

void invokeFooDoSomething() {
    jobject javaFred = FredFactory::getFred(); // Get a Fred jobject
    jobject javaFoo = FooFactory::getFoo(); // Get a Foo jobject
    jobject javaBar = FooFactory::getBar(); // Get a Bar jobject
    jmethodID methodID = getDoSomethingMethodId() // Get the JNI Method ID


    jniEnv->CallVoidMethod(javaFoo,
                           methodID,
                           javaFred, // Woops!  I switched the Fred and Bar parameters!
                           javaBar);

    // << Insert error handling code here to discover the JNI Exception >>
    //  ... This is where the IncompatibleClassChangeError will show up.
}

Java代码示例:

class Bar { ... }

class Fred {
    public int size() { ... }
} 

class Foo {
    public void doSomething(Fred aFred, Bar anotherObject) {
        if (name.size() > 0) { // Will throw a cryptic java.lang.IncompatibleClassChangeError
            // Do some stuff...
        }
    }
}