【笔记】开机启动到SystemServer

可以看到从C++进入Java世界的入口是ZygoteInit.java

下面从ZygoteInit.java的main方法开始

public static void main(String argv[]) {

  if ("start-system-server".equals(argv[i])) {
         startSystemServer = true;
    }

  if (startSystemServer) {
        //创建出SystemServer进程
        Runnable r = forkSystemServer(abiList, zygoteSocketName, zygoteServer);

      }
}

然后会从C代码层，反射调用SystemServer.java的入口方法main()

SystemServer.java

/**
     * The main entry point from zygote.
     */
    public static void main(String[] args) {
        new SystemServer().run();
    }

      //启动各类系统服务（100+）
      startBootstrapServices();
      startCoreServices();
      startOtherServices();

在 startOtherServices()方法最后，所有系统服务都已经启动完成，开始通知ActivityManagerService启动launch应用

       // We now tell the activity manager it is okay to run third party
        // code.  It will call back into us once it has gotten to the state
        // where third party code can really run (but before it has actually
        // started launching the initial applications), for us to complete our
        // initialization.
        mActivityManagerService.systemReady(() -> {
            //started launching 
        }

后面继续launcher应用的启动。