java.lang.LinkageError:ClassCastException [英] java.lang.LinkageError: ClassCastException

问题描述

我确实遇到了TestNG和RESTeasy的一个非常烦人的问题.

I do experience a really annoying problem with TestNG and RESTeasy.

我确实有一个类，该类针对使用RESTeasy框架公开自身的API类运行多个测试.

I do have a class that runs several tests against an API class which uses the RESTeasy framework to expose itself.

但是，如果我让测试通过maven运行(mvn测试)，则会出现以下异常:

However if I let the test run with maven (mvn test), then I get the following exception:

java.lang.LinkageError: ClassCastException: attempting to castjar:file:/C:/Users/rit/.m2/repository/org/jboss/resteasy/jaxrs-api/2.3.0.GA/jaxrs-api-2.3.0.GA.jar!/javax/ws/rs/ext/RuntimeDelegate.classtojar:file:/C:/Users/rit/.m2/repository/org/jboss/resteasy/jaxrs-api/2.3.0.GA/jaxrs-api-2.3.0.GA.jar!/javax/ws/rs/ext/RuntimeDelegate.class
at javax.ws.rs.ext.RuntimeDelegate.findDelegate(RuntimeDelegate.java:126)
at javax.ws.rs.ext.RuntimeDelegate.getInstance(RuntimeDelegate.java:96)
at javax.ws.rs.core.Response$ResponseBuilder.newInstance(Response.java:394)
at javax.ws.rs.core.Response.status(Response.java:116)
at javax.ws.rs.core.Response.status(Response.java:130)
at com.pd.api.TokenAPI_V1.validateAccessToken(TokenAPI_V1.java:141)
at com.test.pd.api.TokenAPI_V1Test.testIfValidAccessTokenReturnsCorrectHTTPHeadersWhenTokenIsNotFound(TokenAPI_V1Test.java:359)

该测试只不过是调用API对象的方法，该方法返回一个Response对象(来自RESTeasy).作为测试框架，我确实使用TestNG.

The test does nothing more than calling a method of the API obejct which returns a Response object (from RESTeasy). As testing framework I do use TestNG.

测试方法

@Test
public void testIfValidAccessTokenReturnsCorrectHTTPHeadersWhenTokenIsNotFound() throws InvalidAccessTokenException {
    Mockito.when(tokenService.validateAccessToken(TestConstants.ACCESS_TOKEN)).thenThrow(new InvalidAccessTokenException());

    Response response = tokenAPI_v1.validateAccessToken(TestConstants.ACCESS_TOKEN, TestConstants.USER_AGENT);
    assert "no-store".equals(response.getMetadata().getFirst("Cache-Control"));
    assert "no-cache".equals(response.getMetadata().getFirst("Pragma"));
}

问题说明

看起来RESTeasy框架将RuntimeDelegate加载到其他类加载器中.如果我看一下源代码，那么RuntimeDelegate(涵盖第126行)有以下方法:

It looks like the RESTeasy framework loads the RuntimeDelegate in a different class loader. If I take a look at the source code, then there is the following method at the RuntimeDelegate (which covers line 126): RuntimeDelegate.java.

因此，与错误相关的主要语句是checkinstanceof:

So the main statement that is related to the error is the instanceof check:

if (!(delegate instanceof RuntimeDelegate))

如果我检查委托实例的类加载器与RuntimeDelegate的类加载器，则得到以下输出:

If I check the classloader of the delegate instance vs the classloader of the RuntimeDelegate, then I get the following output:

delegate.getClass().getClassLoader() -> org.powermock.core.classloader.MockClassLoader@31e46a68

RuntimeDelegate.class.getClassLoader() -> sun.misc.Launcher$AppClassLoader@3c0fabe9

我知道这当然是行不通的，但是我想知道为什么RESTeasy内容被加载到了MockClassLoader中而不是另一个.尤其是因为我不嘲笑经过测试的TokenAPI.

I am aware of that this of course doesn't work but I wonder why the RESTeasy stuff is loaded in the MockClassLoader and not in the other one. Especially as I don't mock the TokenAPI which gets tested.

奇怪的事实

奇怪的是，当我从IntelliJ中运行测试时(我只选择运行给定类中的所有测试，该类包含会产生错误的方法)，然后它就会通过.看来，这与mvn test运行了maven项目中的所有测试(或者至少我猜是这样)有关.

The strange thing is, that when I run the tests out of IntelliJ (I choose only to run all tests from the given class which contains the method that produces the error), then it runs through. It looks like it is somehow related to the fact that mvn test runs all tests from the maven project (or at least that's what I guess).

推荐答案

很遗憾，我无法告诉您发生这种情况的原因，但是我可以告诉您如何解决此问题.

Unfortunately I can't tell you why this happened, but I can tell you how to get around this issue.

问题是，PowerMockito扫描了类路径并还添加了RESTeasy类(它们位于包'javax.ws.*中.)因此，上述RuntimeDelegate由PowerMockito类加载器加载，并导致了以后的问题. ，则将该类与来自其他类加载器的类进行了比较.

The problem was, that PowerMockito scanned tha class path and also added the RESTeasy classes (which are located within the package 'javax.ws.*'. Therefor the above mentioned RuntimeDelegate was loaded by the PowerMockito classloader and caused later the issue, that the class was compared against one from a different classloader.

要解决此问题，请告诉PowerMockito在扫描类时忽略javax.ws包:

To get around this issue, tell PowerMockito to ignore the javax.ws package when scanning for classes:

@PowerMockIgnore({"javax.ws.*"})

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