equinox 环
境下每一个bundle都是由独立的classLoader实现类的装载的。在OSGi
Framework中，Bundle是模块化管理的单元，所有的应用和资源都必须以Bundle作为载体。每个Bundle都有自己的Class
Loader，不同Bundle之间（在同一个VM中）可以通过Import和Export机制共享或者隐藏Package。Class
Loader建立一种Loading Class的代理模型，来实现资源的共享或隐藏。
下面是equinox实现的类的装载代码：
Class findClass(String name, boolean checkParent) throws ClassNotFoundException {
String pkgName = getPackageName(name);
// follow the OSGi delegation model
if (checkParent && parent != null) {
if (name.startsWith(JAVA_PACKAGE))
// 1) if startsWith "java." delegate to parent and terminate search
// we want to throw ClassNotFoundExceptions if a java.* class cannot be loaded from the parent.
return parent.loadClass(name);
else if (isBootDelegationPackage(pkgName))
// 2) if part of the bootdelegation list then delegate to parent and continue of failure
try {
return parent.loadClass(name);
} catch (ClassNotFoundException cnfe) {
// we want to continue
}
}
Class result = null;
// 3) search the imported packages
PackageSource source = findImportedSource(pkgName);
if (source != null) {
// 3) found import source terminate search at the source
result = source.loadClass(name);
if (result != null)
return result;
throw new ClassNotFoundException(name);
}
// 4) search the required bundles
source = findRequiredSource(pkgName);
if (source != null)
// 4) attempt to load from source but continue on failure
result = source.loadClass(name);
// 5) search the local bundle
if (result == null)
result = findLocalClass(name);
if (result != null)
return result;
// 6) attempt to find a dynamic import source; only do this if a required source was not found
if (source == null) {
source = findDynamicSource(pkgName);
if (source != null)
result = source.loadClass(name);
}
// do buddy policy loading
if (result == null && policy != null)
result = policy.doBuddyClassLoading(name);
// last resort; do class context trick to work around VM bugs
if (result == null && findParentResource(name))
result = parent.loadClass(name);
if (result == null)
throw new ClassNotFoundException(name);
return result;
}