通过以上过程就会调用到 SystemServer 类，且是运行在一个名为“ system_server” 的进程中，这个进程为 zygote 的子进程。
虽然 SystemServer 类是运行在 system_server 中的，但是它并不运行在 system_server 的主线程中。
上代码
private static void handleSystemServerProcess( ZygoteConnection.Arguments parsedArgs) throws ZygoteInit.MethodAndArgsCaller { closeServerSocket(); /* * Pass the remaining arguments to SystemServer. * "--nice-name=system_server com.Android.server.SystemServer" */ RuntimeInit.zygoteInit(parsedArgs.remainingArgs);ZygoteInit /* should never reach here */ } public static final void zygo用teInit(String[] argv) throws ZygoteInit.MethodAndArgsCaller { // TODO: Doing this here works, but it seems kind of arbitrary. Find // a better place. The goal is to set it up for applications, but not // tools like am. System.setOut(new AndroidPrintStream(Log.INFO, "System.out")); System.setErr(new AndroidPrintStream(Log.WARN, "System.err")); commonInit(); zygoteInitNative(); int curArg = 0; for ( /* curArg */ ; curArg < argv.length; curArg++) { String arg = argv[curArg]; if (arg.equals("--")) { curArg++; break; } else if (!arg.startsWith("--")) { break; } else if (arg.startsWith("--nice-name=")) { String niceName = arg.substring(arg.indexOf('=') + 1); Process.setArgV0(niceName); } } if (curArg == argv.length) { Slog.e(TAG, "Missing classname argument to RuntimeInit!"); // let the process exit return; } // Remaining arguments are passed to the start class's static main String startClass = argv[curArg++]; String[] startArgs = new String[argv.length - curArg]; System.arraycopy(argv, curArg, startArgs, 0, startArgs.length); invokeStaticMain(startClass, startArgs); } private static void invokeStaticMain(String className, String[] argv) throws ZygoteInit.MethodAndArgsCaller { 用 // We want to be fairly aggressive about heap utilization, to avoid // holding on to a lot of memory that isn't needed. VMRuntime.getRuntime().setTargetHeapUtilization(0.75f); Class<?> cl; try { cl = Class.forName(className); } catch (ClassNotFoundException ex) { throw new RuntimeException( "Missing class when invoking static main " + className, ex); } Method m; try { m = cl.getMethod("main", new Class[] { String[].class }); } catch (NoSuchMethodException ex) { throw new RuntimeException( "Missing static main on " + className, ex); } catch (SecurityException ex) { throw new RuntimeException( "Problem getting static main on " + className, ex); } int modifiers = m.getModifiers();用 if (! (Modifier.isStatic(modif用iers) && Modifier.isPublic(modifiers))) { throw new RuntimeException( "Main method is not用 public and static on " + className); } /* * This throw gets caught in ZygoteInit.main(), which responds * by invoking the exception's run() method. This arrangement * clears up all the stack frames that were required in setting * up the process. */ throw new ZygoteInit.MethodAndArgsCaller(m, argv); }