Java中的NoClassDefFoundError

定义:

Java虚拟机无法在运行时找到在编译时可用的特定类。 如果一个类在编译时存在，但在运行时在java类路径中不可用。

例子:

The class is not in Classpath, there is no sure shot way of knowing it but many times you can just have a look to print System.getproperty("java.classpath") and it will print the classpath from there you can at least get an idea of your actual runtime classpath. A simple example of NoClassDefFoundError is class belongs to a missing JAR file or JAR was not added into classpath or sometimes jar's name has been changed by someone like in my case one of my colleagues has changed tibco.jar into tibco_v3.jar and the program is failing with java.lang.NoClassDefFoundError and I were wondering what's wrong. Just try to run with explicitly -classpath option with the classpath you think will work and if it's working then it's a sure short sign that someone is overriding java classpath. Permission issue on JAR file can also cause NoClassDefFoundError in Java. Typo on XML Configuration can also cause NoClassDefFoundError in Java. when your compiled class which is defined in a package, doesn’t present in the same package while loading like in the case of JApplet it will throw NoClassDefFoundError in Java.

可能的解决方式:

The class is not available in Java Classpath. If you are working in J2EE environment than the visibility of Class among multiple Classloader can also cause java.lang.NoClassDefFoundError, see examples and scenario section for detailed discussion. Check for java.lang.ExceptionInInitializerError in your log file. NoClassDefFoundError due to the failure of static initialization is quite common. Because NoClassDefFoundError is a subclass of java.lang.LinkageError it can also come if one of it dependency like native library may not available. Any start-up script is overriding Classpath environment variable. You might be running your program using jar command and class was not defined in manifest file's ClassPath attribute.

资源:

3种方法解决NoClassDefFoundError

noclassdeffounderror问题模式

如果您有生成代码(EMF等)，可能会有太多的静态初始化器，这会占用所有的堆栈空间。

参见堆栈溢出问题如何增加Java堆栈大小?。

我从SRC库中删除了两个文件后得到了这个消息，当我把它们带回来时，我一直看到这个错误消息。

我的解决方案是:重新启动Eclipse。从那以后我就再没见过这条消息了:-)

Java中的NoClassDefFoundError

定义:

Java虚拟机无法在运行时找到在编译时可用的特定类。 如果一个类在编译时存在，但在运行时在java类路径中不可用。

例子:

The class is not in Classpath, there is no sure shot way of knowing it but many times you can just have a look to print System.getproperty("java.classpath") and it will print the classpath from there you can at least get an idea of your actual runtime classpath. A simple example of NoClassDefFoundError is class belongs to a missing JAR file or JAR was not added into classpath or sometimes jar's name has been changed by someone like in my case one of my colleagues has changed tibco.jar into tibco_v3.jar and the program is failing with java.lang.NoClassDefFoundError and I were wondering what's wrong. Just try to run with explicitly -classpath option with the classpath you think will work and if it's working then it's a sure short sign that someone is overriding java classpath. Permission issue on JAR file can also cause NoClassDefFoundError in Java. Typo on XML Configuration can also cause NoClassDefFoundError in Java. when your compiled class which is defined in a package, doesn’t present in the same package while loading like in the case of JApplet it will throw NoClassDefFoundError in Java.

可能的解决方式:

The class is not available in Java Classpath. If you are working in J2EE environment than the visibility of Class among multiple Classloader can also cause java.lang.NoClassDefFoundError, see examples and scenario section for detailed discussion. Check for java.lang.ExceptionInInitializerError in your log file. NoClassDefFoundError due to the failure of static initialization is quite common. Because NoClassDefFoundError is a subclass of java.lang.LinkageError it can also come if one of it dependency like native library may not available. Any start-up script is overriding Classpath environment variable. You might be running your program using jar command and class was not defined in manifest file's ClassPath attribute.

资源:

3种方法解决NoClassDefFoundError

noclassdeffounderror问题模式

当静态初始化器试图加载一个在运行时不可用的资源包时，也会发生NoClassDefFoundError，例如受影响的类试图从META-INF目录加载一个属性文件，但不存在。如果你没有捕获NoClassDefFoundError，有时你将无法看到完整的堆栈跟踪;为了克服这个问题，你可以临时为Throwable使用一个catch子句:

try {
    // Statement(s) that cause(s) the affected class to be loaded
} catch (Throwable t) {
    Logger.getLogger("<logger-name>").info("Loading my class went wrong", t);
}

我通过禁用所有模块的preDexLibraries来解决我的问题:

dexOptions {
        preDexLibraries false
        ...