问题
I'm using ant to generate javadocs, but get this exception over and over - why?
I'm using JDK version 1.6.0_06.
[javadoc] java.lang.ClassCastException: com.sun.tools.javadoc.ClassDocImpl cannot be cast to com.sun.javadoc.AnnotationTypeDoc
[javadoc] at com.sun.tools.javadoc.AnnotationDescImpl.annotationType(AnnotationDescImpl.java:46)
[javadoc] at com.sun.tools.doclets.formats.html.HtmlDocletWriter.getAnnotations(HtmlDocletWriter.java:1739)
[javadoc] at com.sun.tools.doclets.formats.html.HtmlDocletWriter.writeAnnotationInfo(HtmlDocletWriter.java:1713)
[javadoc] at com.sun.tools.doclets.formats.html.HtmlDocletWriter.writeAnnotationInfo(HtmlDocletWriter.java:1702)
[javadoc] at com.sun.tools.doclets.formats.html.HtmlDocletWriter.writeAnnotationInfo(HtmlDocletWriter.java:1681)
[javadoc] at com.sun.tools.doclets.formats.html.FieldWriterImpl.writeSignature(FieldWriterImpl.java:130)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.FieldBuilder.buildSignature(FieldBuilder.java:184)
[javadoc] at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
[javadoc] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[javadoc] at java.lang.reflect.Method.invoke(Method.java:597)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.FieldBuilder.invokeMethod(FieldBuilder.java:114)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.AbstractBuilder.build(AbstractBuilder.java:90)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.AbstractMemberBuilder.build(AbstractMemberBuilder.java:56)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.FieldBuilder.buildFieldDoc(FieldBuilder.java:158)
[javadoc] at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source)
[javadoc] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[javadoc] at java.lang.reflect.Method.invoke(Method.java:597)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.FieldBuilder.invokeMethod(FieldBuilder.java:114)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.AbstractBuilder.build(AbstractBuilder.java:90)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.AbstractMemberBuilder.build(AbstractMemberBuilder.java:56)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.ClassBuilder.buildFieldDetails(ClassBuilder.java:301)
[javadoc] at sun.reflect.GeneratedMethodAccessor43.invoke(Unknown Source)
[javadoc] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[javadoc] at java.lang.reflect.Method.invoke(Method.java:597)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.ClassBuilder.invokeMethod(ClassBuilder.java:101)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.AbstractBuilder.build(AbstractBuilder.java:90)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.ClassBuilder.buildClassDoc(ClassBuilder.java:124)
[javadoc] at sun.reflect.GeneratedMethodAccessor19.invoke(Unknown Source)
[javadoc] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[javadoc] at java.lang.reflect.Method.invoke(Method.java:597)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.ClassBuilder.invokeMethod(ClassBuilder.java:101)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.AbstractBuilder.build(AbstractBuilder.java:90)
[javadoc] at com.sun.tools.doclets.internal.toolkit.builders.ClassBuilder.build(ClassBuilder.java:108)
[javadoc] at com.sun.tools.doclets.formats.html.HtmlDoclet.generateClassFiles(HtmlDoclet.java:155)
[javadoc] at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.generateClassFiles(AbstractDoclet.java:164)
[javadoc] at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.startGeneration(AbstractDoclet.java:106)
[javadoc] at com.sun.tools.doclets.internal.toolkit.AbstractDoclet.start(AbstractDoclet.java:64)
[javadoc] at com.sun.tools.doclets.formats.html.HtmlDoclet.start(HtmlDoclet.java:42)
[javadoc] at com.sun.tools.doclets.standard.Standard.start(Standard.java:23)
[javadoc] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[javadoc] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[javadoc] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[javadoc] at java.lang.reflect.Method.invoke(Method.java:597)
[javadoc] at com.sun.tools.javadoc.DocletInvoker.invoke(DocletInvoker.java:215)
[javadoc] at com.sun.tools.javadoc.DocletInvoker.start(DocletInvoker.java:91)
[javadoc] at com.sun.tools.javadoc.Start.parseAndExecute(Start.java:340)
[javadoc] at com.sun.tools.javadoc.Start.begin(Start.java:128)
[javadoc] at com.sun.tools.javadoc.Main.execute(Main.java:41)
[javadoc] at com.sun.tools.javadoc.Main.main(Main.java:31)
回答1:
It looks like this has been reported as a Java bug. It appears to be caused by using annotations from a 3rd party library (like JUnit) and not including the jar with that annotation in the javadoc invocation.
If that is the case, just use the -classpath option on javadoc and include the extra jar files.
回答2:
I have some idea regarding this problem but this not exact solution to get.
If you give single comment line \\\\ before annotation and try to run the javadoc once again. This problem will solve
Eg: sample.java File
@ChannelPipeline
Makes changes in
\\\\@ChannelPipeline
Try to run javadoc command once again. Now Class Cast Exception won't occur
回答3:
I got this problem too. I can compile properly without any errors or warnings. But when I generating javadoc , I got below error.
[javadoc] java.lang.ClassCastException: com.sun.tools.javadoc.ClassDocImpl cannot be cast to com.sun.javadoc.AnnotationTypeDoc
Here is my classpath loading for my third-party-libs ...
<path id="build.classpath">
<fileset dir=".">
<include name="libs/*.jar" />
</fileset>
At my java compile target ..
<target name="compile" depends="clean, makedir">
<javac includeantruntime="false" srcdir="${src.dir}" destdir="${build.dir}" classpathref="build.classpath">
<compilerarg value="-Xlint:unchecked"/>
</javac>
And at my javadoc target...
<target name="docs" depends="compile">
<javadoc packagenames="src" sourcepath="${src.dir}" destdir="${docs.dir}"
failonerror="no"
author="true"
version="true"
windowtitle="${Name} API"
doctitle="${Name}"
bottom="Copyright © 2014 ColayHIlls.com . All Rights Reserved.">
<fileset dir="${src.dir}">
<include name="main/java/com/colayhills/jpcenter/business/service/**" />
</fileset>
</javadoc>
<echo message="java docs has been generated!"/>
</target>
So , I added classpathref="build.classpath" option to <javadoc tag. Now It is fine for me.
回答4:
There is another way to get a ClassCastException (1.8.0_101 is failing currently):
java.lang.ClassCastException: com.sun.tools.javadoc.MethodDocImpl cannot be cast to com.sun.tools.javadoc.AnnotationTypeElementDocImpl
It will happen when javadoc encounters a reference to a annotation method in javadoc text before processing the same annotation for the first time used in code. Take these two classes:
/**
** {@link javax.annotation.Generated#value()}
*/
public class TestClass1 {}
@Generated("sometext")
public class TestClass2 {}
The bug is order dependent. If javadoc processes TestClass1 first, the ClassCastException will be thrown. If javadoc processes TestClass2 first, it will complete fine. The bug is reported as JDK-8170444.
As a workaround, don't link to annotation methods in your documentation text.
来源：https://stackoverflow.com/questions/44853/why-am-i-getting-a-classcastexception-when-generating-javadocs