确保在module:app和module:lib中匹配:

android {
    compileSdkVersion 23
    buildToolsVersion '22.0.1'
    packagingOptions {
    }

    defaultConfig {
        minSdkVersion 17
        targetSdkVersion 23
        versionCode 11
        versionName "2.1"
    }

同一项目的两个不同的签出副本

In my case, the problem was Eclipse's inability to differentiate between two different copies of the same project. I have one locked on trunk (SVN version control) and the other one working in one branch at a time. I tried out one change in the working copy as a JUnit test case, which included extracting a private inner class to be a public class on its own and while it was working, I open the other copy of the project to look around at some other part of the code that needed changes. At some point, the NoClassDefFoundError popped up complaining that the private inner class was not there; double-clicking in the stack trace brought me to the source file in the wrong project copy.

关闭项目的主干副本并再次运行测试用例可以解决这个问题。

I have had an interesting issue wiht NoClassDefFoundError in JavaEE working with Liberty server. I was using IMS resource adapters and my server.xml had already resource adapter for imsudbJXA.rar. When I added new adapter for imsudbXA.rar, I would start getting this error for instance objects for DLIException, IMSConnectionSpec or SQLInteractionSpec. I could not figure why but I resolved it by creating new server.xml for my work using only imsudbXA.rar. I am sure using multiple resource adapters in server.xml is fine, I just had no time to look into that.

我发现，当使用运行时发现的不兼容的类版本编译代码时，有时会得到NoClassDefFound错误。我记得的具体实例是apache axis库。在我的运行时类路径上实际上有2个版本，它正在挑选过时和不兼容的版本，而不是正确的版本，导致NoClassDefFound错误。这是在一个命令行应用程序中，我正在使用类似的命令。

set classpath=%classpath%;axis.jar

我能够让它拿起正确的版本使用:

set classpath=axis.jar;%classpath%;

Java无法在运行时找到类A。 Class A在maven项目ArtClient中，来自不同的工作空间。 因此，我将ArtClient导入到Eclipse项目中。 我的两个项目使用ArtClient作为依赖项。 我将这些库引用更改为项目引用(构建路径->配置构建路径)。

问题就这样解决了。

当我没有在项目的Java Build Path中的“Order and export”选项卡上导出一个类时，我得到了NoClassDefFound错误。确保在添加到项目构建路径的任何依赖项的“Order and Export”选项卡中添加一个复选标记。请参见Eclipse警告:XXXXXXXXXXX.jar将不会被导出或发布。可能会导致运行时ClassNotFoundExceptions。