java ClassLoader.defineClass 抛出的 ClassCircularityError
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ClassCircularityError thrown by ClassLoader.defineClass
提问by Jim
I'm loading classes using a custom class loader. For the most part, everything works, but sometimes when I load particularly complex projects/libraries, I get a strange bug:
我正在使用自定义类加载器加载类。在大多数情况下，一切正常，但有时当我加载特别复杂的项目/库时，我会遇到一个奇怪的错误：
Exception in thread "main" java.lang.ClassCircularityError:
org/apache/commons/codec/binary/Hex
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.lang.ClassLoader.defineClass(ClassLoader.java:466)
at my.custom.class.Loader.loadClass(...)
Looking at the Javadocs, I wouldn't expect defineClassto throw this particular error. org/apache/commons/codec/binary/Hexis the class I'm trying to load. It's almost as if defineClasswants a copy of the class before it'll define the class - which makes no sense to me.
查看 Javadocs，我不希望defineClass抛出这个特定的错误。 org/apache/commons/codec/binary/Hex是我正在尝试加载的课程。这几乎就像defineClass在定义类之前想要类的副本一样 - 这对我来说没有意义。
Ideas?
想法？
回答by Pa?lo Ebermann
A ClassCircularityErroris thrown when some class is a (indirect) superclass of itself, some interface (indirectly) extends itself or similar.
ClassCircularityError当某个类是其自身的（间接）超类、某个接口（间接）扩展自身或类似时，会抛出A。
This should normally not occur as a well-behaved compiler will not produce such classes, but using different versions of a library (or using several libraries containing different versions of a class) could bring this problem.
这通常不会发生，因为行为良好的编译器不会生成此类类，但使用不同版本的库（或使用包含不同版本类的多个库）可能会带来此问题。
Scan your libraries for double class names, in particular have a look if there are multiple versions of the mentioned org.apache.commons.codec.binary.Hexclass.
扫描您的库中是否有双类名称，特别是看看是否有提到的org.apache.commons.codec.binary.Hex类的多个版本。
