protected Class<?> loadClass(String name, boolean resolve)
    throws ClassNotFoundException
{
        // 缓存查询
        Class<?> c = findLoadedClass(name);
        if (c == null) {
            // parent加载器查询
            try {
                if (parent != null) {
                    c = parent.loadClass(name, false);
                } else {
                    c = findBootstrapClassOrNull(name);
                }
            } catch (ClassNotFoundException e) {
                // 父类加载器未查询到没有查询到
            }

            if (c == null) {
                // 缓存和父加载器都未查询到，执行查询
                c = findClass(name);
            }
        }
        return c;
}

public class PathClassLoader extends BaseDexClassLoader {

    public PathClassLoader(String dexPath, ClassLoader parent) {
        super(dexPath, null, null, parent);
    }

   
    public PathClassLoader(String dexPath, String librarySearchPath, ClassLoader parent) {
        super(dexPath, null, librarySearchPath, parent);
    }


    @libcore.api.CorePlatformApi
    public PathClassLoader(
            String dexPath, String librarySearchPath, ClassLoader parent,
            ClassLoader[] sharedLibraryLoaders) {
        super(dexPath, librarySearchPath, parent, sharedLibraryLoaders);
    }
}


public class DexClassLoader extends BaseDexClassLoader {

    public DexClassLoader(String dexPath, String optimizedDirectory,
            String librarySearchPath, ClassLoader parent) {
        super(dexPath, null, librarySearchPath, parent);
    }
}

public class BaseDexClassLoader extends ClassLoader {

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        // First, check whether the class is present in our shared libraries.
        if (sharedLibraryLoaders != null) {
            for (ClassLoader loader : sharedLibraryLoaders) {
                try {
                    return loader.loadClass(name);
                } catch (ClassNotFoundException ignored) {
                }
            }
        }
        // Check whether the class in question is present in the dexPath that
        // this classloader operates on.
        List<Throwable> suppressedExceptions = new ArrayList<Throwable>();
        Class c = pathList.findClass(name, suppressedExceptions);
        if (c == null) {
            ClassNotFoundException cnfe = new ClassNotFoundException(
                    "Didn't find class \"" + name + "\" on path: " + pathList);
            for (Throwable t : suppressedExceptions) {
                cnfe.addSuppressed(t);
            }
            throw cnfe;
        }
        return c;
    }
    
}

public class App extends Application {

    @Override
    public void onCreate() {
        super.onCreate();

        ClassLoader loader = getClassLoader();

        log("Application:" + loader.getClass().getName());
        log("String:" + String.class.getClassLoader().getClass().getName());
        log("CustomClass:" + CustomClass.class.getClassLoader().getClass().getName());

        registerActivityLifecycleCallbacks(new InnerActivityLifecycleCallbacks() {
            @Override
            public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
              log("InnerActivityLifecycleCallbacks:"+getClassLoader().getClass().getName());
              log("activity:" + activity.getClass().getClassLoader().getClass().getName());
            }
        });
    }
}