什么是 Java 中的 IncompatibleClassChangeError 异常？
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What is a IncompatibleClassChangeError exception in Java?
提问by Dimitri
i am working on a small application and I am trying to use Hibernate Annotations to map my entities. I wanted to test if everything is alright when i got this exception :
我正在开发一个小应用程序，我正在尝试使用 Hibernate Annotations 来映射我的实体。当我收到此异常时，我想测试是否一切正常：
Exception in thread "main" java.lang.ExceptionInInitializerError
at fr.cc2i.intervention.dao.main.Main$HibernateUtil.<clinit>(Main.java:48)
at fr.cc2i.intervention.dao.main.Main.test(Main.java:21)
at fr.cc2i.intervention.dao.main.Main.main(Main.java:32)
Caused by: java.lang.IncompatibleClassChangeError: Implementing class
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632)
at java.lang.ClassLoader.defineClass(ClassLoader.java:616)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access package fr.cc2i.intervention.dao.main;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import fr.cc2i.intervention.dao.beans.Client;
import fr.cc2i.intervention.dao.beans.Contrat;
public class Main {
public static void test(){
Client c = new Client();
c.setCode("123343");
c.setAdresse("fkhdhdmh");
c.setNom("dgsfhgsdfgs");
c.setPhone("53456464");
c.setContrat(new Contrat());
Session session = HibernateUtil.getSession();
session.beginTransaction();
session.save(c);
session.getTransaction().commit();
}
/**
* @param args
*/
public static void main(String[] args) {
Main.test();
}
public static class HibernateUtil {
private static final SessionFactory sessionFactory;
static {
try {
sessionFactory = new AnnotationConfiguration()
.configure().buildSessionFactory();
} catch (Throwable ex) {
// Log exception!
throw new ExceptionInInitializerError(ex);
}
}
public static Session getSession()
throws HibernateException {
return sessionFactory.openSession();
}
}
}
0(URLClassLoader.java:58)
at java.net.URLClassLoader.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
at fr.cc2i.intervention.dao.main.Main$HibernateUtil.<clinit>(Main.java:44)
... 2 more
Can someone explain what is this exception ? This is the first time i see it. Here is the main of my application :
有人可以解释一下这个例外是什么吗？这是我第一次看到。这是我的应用程序的主要内容：
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">org.hsqldb.jdbcDriver</property>
<property name="connection.url">jdbc:hsqldb:hsql://localhost</property>
<property name="connection.username">sa</property>
<property name="connection.password"></property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.HSQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<mapping package="fr.cc2i.intervention.dao.beans.Client" />
<mapping class="fr.cc2i.intervention.dao.beans.Contrat" />
<mapping class="fr.cc2i.intervention.dao.beans.Intervention" />
<mapping class="fr.cc2i.intervention.dao.beans.Technicien" />
</session-factory>
</hibernate-configuration>
My hibernate config is very simple :
我的休眠配置非常简单：
<properties>
<org.springframework.version>3.0.3.RELEASE</org.springframework.version>
<hibernate.version>3.6.0.Beta1</hibernate.version></properties>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
<version>${hibernate.version}</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
Here is the hibernate maven dependency i am using :
这是我正在使用的休眠 maven 依赖项：
interface Fooable {
void foo();
}
class FooImpl implements Fooable {
public void foo() {
/* Do something... */
}
}
Can someone help me please ??
有人能帮助我吗 ？？
采纳答案by erickson
It means that at some point, an interfacewas changed to a class, but an implementer of the original interface was not modified and recompiled to accommodate this (incompatible) change.
这意味着在某些时候， aninterface被更改为 a class，但原始接口的实现者并未修改和重新编译以适应此（不兼容）更改。
For example, consider the following types:
例如，考虑以下类型：
abstract class Fooable {
public abstract void foo();
}
Now suppose Fooableis modified and recompiled, but FooImplis not:
现在假定Fooable被修改并重新编译，但是FooImpl是不是：
回答by Julian Bonilla
Which application server are you using? Could be a duplicate or conflicting hibernate jar.
您使用的是哪个应用服务器？可能是重复或冲突的休眠 jar。
回答by RonU
Right, erickson has identified the issue correctly.
是的，埃里克森正确地识别了问题。
This is likely caused by having two conflicting versions of the same type definition in your classpath. For example, library-version2.jar defines some stuff, but you've also got library-version5.jar in your classpath.
这可能是由于类路径中具有相同类型定义的两个冲突版本造成的。例如，library-version2.jar 定义了一些东西，但您的类路径中也有 library-version5.jar。
At runtime, this results in the pain and suffering erickson describes.
在运行时，这会导致 erickson 描述的痛苦和痛苦。
回答by Andreas Dolk
Double check if all your libraries are compatible. Try the same with a stable version of hibernate, there's a chance that the beta is defect or the hibernate 3.6.0 beta POM has some incompatible dependencies.
仔细检查您的所有库是否兼容。使用稳定版本的 hibernate 尝试相同的方法，可能是 beta 存在缺陷，或者 hibernate 3.6.0 beta POM 有一些不兼容的依赖项。
Try to build it without maven and with hibernate 3.6.0 beta1 libraries from the official servers.
尝试在没有 maven 的情况下使用官方服务器中的 hibernate 3.6.0 beta1 库构建它。
OK - your problem is not a bug but a new feature. The release notes for Hibernate 3.6.0 Beta2 note a major change to the previous beta: the AnnotationConfiguration is now totally deprecated. So you should (a) update to the most recent beta (Beta3) if you want to keep a 3.6.0 version and (b) do not continue using the AnnotationConfiguration.
好的 - 您的问题不是错误而是新功能。Hibernate 3.6.0 Beta2 的发行说明指出了对之前测试版的重大更改：AnnotationConfiguration 现在已完全弃用。因此，如果您想保留 3.6.0 版本，您应该 (a) 更新到最新的测试版 (Beta3)，并且 (b) 不要继续使用 AnnotationConfiguration。
回答by Pascal Thivent
JDK 1.4 support has been dropped in 3.6. So Hibernate Annotations has been merged back into Core and there is no more need to have both Configurationand AnnotationConfigurationand the later should not be used in 3.6.x (actually, you should probably use the JPA EntityManager, not the core API, but this is another story).
JDK 1.4 支持已在 3.6 中删除。因此 Hibernate Annotations 已合并回 Core 中，不再需要同时使用Configuration和AnnotationConfiguration，后者不应在 3.6.x 中使用（实际上，您可能应该使用 JPA EntityManager，而不是核心 API，但这是另一回事）。
But my real advice would be to use the 3.5.xbranch of Hibernate, not the 3.6.x. As we already saw, the Hibernate team is introducing big changes in 3.6, which is on top of that still in Beta, and unless you are following the changes closely, you'll face some surprises and won't find many resources on the internet yet. Just use Hibernate 3.5 (3.5.5-Final at the time of writing this).
但我真正的建议是使用Hibernate的3.5.x分支，而不是 3.6.x。正如我们已经看到的，Hibernate 团队在 3.6 中引入了重大变化，这是在 Beta 之上的，除非您密切关注这些变化，否则您将面临一些惊喜，并且不会在互联网上找到很多资源然而。只需使用 Hibernate 3.5（在撰写本文时为 3.5.5-Final）。
回答by zawhtut
I write this to help whoever lookup to this error . Sometimes jar files coming from Spring Roo generated pom.xml and Tomcat Server Runtime libraries conflict and produced this error during unit testing. While building frontend technology like Flex, Server runtime libraries are not necessary to present in the classpath, so simply remove the Server runtime libraries from classpath.
我写这篇文章是为了帮助任何查找此错误的人。有时来自 Spring Roo 的 jar 文件生成的 pom.xml 和 Tomcat Server Runtime 库冲突并在单元测试期间产生此错误。在构建像 Flex 这样的前端技术时，服务器运行时库不需要出现在类路径中，因此只需从类路径中删除服务器运行时库。
