我正在尝试运行 Modular Java 书中的示例并面临 ClassNotFoundException。错误的要点是我有 2 个捆绑包。
捆绑包 1 称为索引。
Bundle 2 是一个打包的 Compass 项目。
捆绑包 1 使用捆绑包 2，并在其 list 的“导入包” header 中声明了它使用的捆绑包 2 中的包。 Bundle 2 也导出相同的包。
索引 (Bundle 1) 使用的 Bundle 2 的类，调用了 Bundle 2 内部的更多类。这些类的包也由 Bundle 2 导出。但是每当我在 Felix(使用 Pax-runner)上部署这些时，启动失败并出现以下错误。
[FelixDispatchQueue] DEBUG main-findmyjar.index - BundleEvent STOPPED - main-findmyjar.index
ERROR: Bundle main-findmyjar.index [7] Error starting file:bundles/main-findmyjar.index_1.0.0.SNAPSHOT.jar (org.osgi.framework.BundleException: Activator start error in bundle main-findmyjar.index [7].)
org.compass.core.config.ConfigurationException: Failed to instantiate [org.compass.core.config.binding.metadata.AsmMetaDataReader], please verify class type at setting [compass.scanner.reader]; nested exception is java.lang.ClassNotFoundException: org.compass.core.config.binding.metadata.AsmMetaDataReader
java.lang.ClassNotFoundException: org.compass.core.config.binding.metadata.AsmMetaDataReader
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.compass.core.util.ClassUtils.forName(ClassUtils.java:90)
at org.compass.core.config.CompassSettings.getSettingAsInstance(CompassSettings.java:304)
at org.compass.core.config.binding.metadata.MetaDataReaderFactory.getMetaDataReader(MetaDataReaderFactory.java:35)
at org.compass.core.config.binding.AbstractClassMetaDataMappingBinding.setUpBinding(AbstractClassMetaDataMappingBinding.java:24)
at org.compass.annotations.config.binding.AnnotationsMappingBinding.setUpBinding(AnnotationsMappingBinding.java:93)
at org.compass.core.config.CompassMappingBinding.setUpBinding(CompassMappingBinding.java:56)
at org.compass.core.config.CompassConfiguration.getMappingBinding(CompassConfiguration.java:121)
at org.compass.core.config.CompassConfiguration.addClass(CompassConfiguration.java:500)
at org.gt.osgi.findmyjar.index.internal.Activator.getCompass(Activator.java:40)
at org.gt.osgi.findmyjar.index.internal.Activator.start(Activator.java:35)
at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:645)
at org.apache.felix.framework.Felix.activateBundle(Felix.java:1977)
at org.apache.felix.framework.Felix.startBundle(Felix.java:1895)
at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1191)
at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:295)
at java.lang.Thread.run(Thread.java:662)
[FelixDispatchQueue] DEBUG main-findmyjar.index - FrameworkEvent ERROR - main-findmyjar.index
org.osgi.framework.BundleException: Activator start error in bundle main-findmyjar.index [7].
at org.apache.felix.framework.Felix.activateBundle(Felix.java:2027)
at org.apache.felix.framework.Felix.startBundle(Felix.java:1895)
at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1191)
at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:295)
at java.lang.Thread.run(Thread.java:662)
Caused by: org.compass.core.config.ConfigurationException: Failed to instantiate [org.compass.core.config.binding.metadata.AsmMetaDataReader], please verify class type at setting [compass.scanner.reader]; nested exception is java.lang.ClassNotFoundException: org.compass.core.config.binding.metadata.AsmMetaDataReader
at org.compass.core.config.CompassSettings.getSettingAsInstance(CompassSettings.java:306)
at org.compass.core.config.binding.metadata.MetaDataReaderFactory.getMetaDataReader(MetaDataReaderFactory.java:35)
at org.compass.core.config.binding.AbstractClassMetaDataMappingBinding.setUpBinding(AbstractClassMetaDataMappingBinding.java:24)
at org.compass.annotations.config.binding.AnnotationsMappingBinding.setUpBinding(AnnotationsMappingBinding.java:93)
at org.compass.core.config.CompassMappingBinding.setUpBinding(CompassMappingBinding.java:56)
at org.compass.core.config.CompassConfiguration.getMappingBinding(CompassConfiguration.java:121)
at org.compass.core.config.CompassConfiguration.addClass(CompassConfiguration.java:500)
at org.gt.osgi.findmyjar.index.internal.Activator.getCompass(Activator.java:40)
at org.gt.osgi.findmyjar.index.internal.Activator.start(Activator.java:35)
at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:645)
at org.apache.felix.framework.Felix.activateBundle(Felix.java:1977)
... 4 more
Caused by: java.lang.ClassNotFoundException: org.compass.core.config.binding.metadata.AsmMetaDataReader
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:247)
at org.compass.core.util.ClassUtils.forName(ClassUtils.java:90)
at org.compass.core.config.CompassSettings.getSettingAsInstance(CompassSettings.java:304)
... 14 more
[FelixDispatchQueue] DEBUG org.apache.felix.framework - BundleEvent STARTED - org.apache.felix.framework
[FelixDispatchQueue] DEBUG org.apache.felix.framework - FrameworkEvent STARTED - org.apache.felix.framework
任何可能是问题的线索？
这是 list 。
Manifest-Version: 1.0
Export-Package: org.gt.osgi.findmyjar.index;uses:="org.gt.osgi.findmyj
ar.domain";version="1.0.0.SNAPSHOT"
Private-Package: org.gt.osgi.findmyjar.index.internal
Ignore-Package: org.gt.osgi.findmyjar.index.internal
Built-By: tyagig
Tool: Bnd-0.0.255
Bundle-Name: main-findmyjar.index
Created-By: Apache Maven Bundle Plugin
Build-Jdk: 1.6.0_32
Bundle-Version: 1.0.0.SNAPSHOT
Bnd-LastModified: 1357910690482
Bundle-ManifestVersion: 2
Bundle-Activator: org.gt.osgi.findmyjar.index.internal.Activator
Bundle-Description: Generated using Pax-Construct
Bundle-SymbolicName: main-findmyjar.index
Import-Package: org.compass.core,org.compass.core.config,org.compass.c
ore.config.binding.metadata,org.gt.osgi.findmyjar.domain;version="1.0
.0.SNAPSHOT",org.gt.osgi.findmyjar.index;version="1.0.0.SNAPSHOT",org
.osgi.framework
最佳答案
好像您有一个 org.compass.core.util.ClassUtils，它执行 Class.forName()，从而解决问题。
如果 ClassUtils 在包 2 中，并且没有提供明确的类加载器来使用，它将默认为包类加载器。 bundleclassloader 只能实例化对 bundle2 可见的类(在整个类图中)。
它尝试加载的设置很可能是 bundle1 中指定的一个类，该类不可见。
解决方案是在动态加载类或查看类加载器伙伴机制时将类加载器从 bundle1 传递到 bundle2。有一个旧的 article 可以更清楚地解释这一点。