java.lang.NoClassDefFoundError：无法初始化类com.google.api.client.util.Data [英] java.lang.NoClassDefFoundError: Could not initialize class com.google.api.client.util.Data

问题描述

编程时出现错误：

"java.lang.NoClassDefFoundError: Could not initialize class com.google.api.client.util.Data"

如何解决？

推荐答案

方式解决java.lang.NoClassDefFoundError的问题是： - 点击链接。

The ways to resolve the java.lang.NoClassDefFoundError are :- Follow the link.

当Java虚拟机不是
能够在
编译时在运行时找到特定的类时，Java中出现NoClassDefFoundError 。例如，如果我们有一个来自类的方法调用或
访问类的任何静态成员，并且该类在运行时没有
，则JVM将抛出NoClassDefFoundError。这是
很重要，要理解这与
ClassNotFoundException不同，后者在尝试仅在
运行时加载类时出现，而名称是在运行时提供的，而不是在编译
时间。许多Java开发人员混淆了这两个错误而感到困惑。

NoClassDefFoundError in Java comes when Java Virtual Machine is not able to find a particular class at runtime which was available during compile time. For example if we have a method call from a class or accessing any static member of a Class and that class is not available during run-time then JVM will throw NoClassDefFoundError. It’s important to understand that this is different than ClassNotFoundException which comes while trying to load a class at run-time only and name was provided during runtime not on compile time. Many Java developer mingle this two Error and gets confused.

简而言之，如果在
编译时出现类但在java类路径中不可用，则会出现NoClassDefFoundError运行。
通常，当你得到
时，你会在日志中看到以下行.NoClassDefFoundError：

In short NoClassDefFoundError will come if a class was present during compile time but not available in java classpath during runtime. Normally you will see below line in log when you get NoClassDefFoundError:

如何解决java.lang 。 NoClassDefFoundError ：

How to resolve java.lang.NoClassDefFoundError:

1. Java Classpath中没有类。


2. 您可能正在使用jar命令运行程序，并且未在清单文件的ClassPath属性中定义类。


3. 任何启动脚本都会覆盖Classpath环境变量。


4. 因为NoClassDefFoundError是java.lang.LinkageError的子类，所以如果其中一个依赖项（如本机库）可能不可用，也会出现这种情况。


5. 检查日志文件中的java.lang.ExceptionInInitializerError。由于静态初始化失败而导致的NoClassDefFoundError非常常见。


6. 如果您在J2EE环境中工作，那么多个类加载器中的Class的可见性也会导致java.lang.NoClassDefFoundError，请参阅示例和场景部分详细讨论。

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

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