想尝试一种新的热修复方式，替换应用的ClassLoader，在loadclass中如果碰到修复类存在，则替换掉原来的类，但是失败了，记录下历程：
首先自定义一个ClassLoader

public class MyPathClassLoader extends BaseDexClassLoader {
    private static final String TAG = "MyPathClassLoader";
    public MyPathClassLoader(String dexPath, ClassLoader parent) {
        super(dexPath, null, null, parent);
        Log.d(TAG, "dexpath1: "+dexPath);
    }

    public MyPathClassLoader(String dexPath, String librarySearchPath, ClassLoader parent) {
        super(dexPath, null, librarySearchPath, parent);
        Log.d(TAG, "dexpath2: "+dexPath + " librarySearchPath:"+ librarySearchPath);
    }

    @Override
    public Class<?> loadClass(String name) throws ClassNotFoundException {
        Log.d(TAG, "loadClass: "+name);
        return super.loadClass(name);
    }


    @Override
    protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
        Log.d(TAG, "loadClass : "+name +" resolve:"+resolve);
        return super.loadClass(name, resolve);
    }

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        Log.d(TAG, "findClass: "+name);
        return super.findClass(name);
    }

    @Override
    public String findLibrary(String name) {
        Log.d(TAG, "findLibrary: "+name);
        return super.findLibrary(name);
    }
}

在application的attachBaseContext方法中替换classloader，替换除了application之外的所有类的classloader，

override fun attachBaseContext(base: Context) {
        super.attachBaseContext(base)

        val appInfo: ApplicationInfo = applicationInfo
        val apkPath = appInfo.sourceDir
     val classLoader =
            MyPathClassLoader(apkPath, classLoader)
        hookPackageClassLoader(base, classLoader)
}

 private fun hookPackageClassLoader(context: Context, appClassLoaderNew: ClassLoader): Boolean {
        try {
            val packageInfoField: Field =
                Class.forName("android.app.ContextImpl").getDeclaredField("mPackageInfo")
            packageInfoField.isAccessible = true
            val loadedApkObject: Any = packageInfoField.get(baseContext)
            var LoadedApkClass = Class.forName("android.app.LoadedApk")
//            val getClassLoaderMethod: Method = LoadedApkClass.getDeclaredMethod("getClassLoader")
//            val appClassLoaderOld = getClassLoaderMethod.invoke(loadedApkObject) as ClassLoader
            val appClassLoaderField: Field = LoadedApkClass.getDeclaredField("mClassLoader")
            appClassLoaderField.isAccessible = true
            appClassLoaderField.set(loadedApkObject, appClassLoaderNew)
            return true
        } catch (ignored: Throwable) {
            Log.d("MyPathClassLoader", "error:"+ignored.message)
        }
        return false
    }

但是在MainActivity测试效果时发现TestA类，并没有由自定义的类加载器加载，而是PathClassLoader加载的，应该是由于android N混合编译，安装过程中提前加载了部分热点类导致的，实验失败。。

  override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Log.d("MyPathClassLoader", "testa classloader:"+TestA().javaClass.classLoader.toString())

        TestA().doSomething()
        Log.d("MyPathClassLoader", "classcloader:"+MainActivity.javaClass.classLoader.toString())

如果继续下去，应该跟tinker一样了，所以没有继续。如果想尝试asm直接更新编译后的class，应该会导致应用校验问题，其他的java后端的hotreload方法，由于android使用的不是jvm虚拟机也无法使用，比如JRebel和HotSwap，大家还有啥好的想法吗
refer：https://cloud.tencent.com/developer/article/1012644
https://mp.weixin.qq.com/s?__biz=MzAwNDY1ODY2OQ==&mid=2649286341&idx=1&sn=054d595af6e824cbe4edd79427fc2706&scene=0#wechat_redirect