源码版本：Android-4.4.4_r2
提示：大部分分析直接注释在代码内。
相关文章：
【分析】dalvik虚拟机启动过程（一）
【分析】dalvik虚拟机启动过程（二）
在AndroidRuntime::start中调用AndroidRuntime::startVm函数启动了虚拟机，然后又调用了AndroidRuntime::startReg函数注册Android函数：
/* * 向 VM 注册Android本地函数。 * Register android native functions with the VM. *//*static*/ int AndroidRuntime::startReg(JNIEnv* env){// 这个函数还不知道是干嘛的！/** This hook causes all future threads created in this process to be* attached to the JavaVM. (This needs to go away in favor of JNI* Attach calls.)*/androidSetCreateThreadFunc((android_create_thread_fn) javaCreateThreadEtc);ALOGV("— registering native functions —\n");/** Every "register" function calls one or more things that return* a local reference (e.g. FindClass). Because we haven't really* started the VM yet, they're all getting stored in the base frame* and never released. Use Push/Pop to manage the storage.*/env->PushLocalFrame(200);// gRegJNI是一个函数列表，这些函数会注册一些本地函数。if (register_jni_procs(gRegJNI, NELEM(gRegJNI), env) < 0) {env->PopLocalFrame(NULL);return -1;}env->PopLocalFrame(NULL);//createJavaThread("fubar", quickTest, (void*) "hello");return 0;}gRegJNI：static const RegJNIRec gRegJNI[] = {……REG_JNI(register_android_util_Log),……};拿REG_JNI(register_android_util_Log)来说，，函数register_jni_procs会调用register_android_util_Log：/* * JNI registration. */static JNINativeMethod gMethods[] = {/* name, signature, funcPtr */{ "isLoggable","(Ljava/lang/String;I)Z", (void*) android_util_Log_isLoggable },{ "println_native", "(IILjava/lang/String;Ljava/lang/String;)I", (void*) android_util_Log_println_native },};int register_android_util_Log(JNIEnv* env){jclass clazz = env->FindClass("android/util/Log");if (clazz == NULL) {ALOGE("Can't find android/util/Log");return -1;}levels.verbose = env->GetStaticIntField(clazz, env->GetStaticFieldID(clazz, "VERBOSE", "I"));levels.debug = env->GetStaticIntField(clazz, env->GetStaticFieldID(clazz, "DEBUG", "I"));levels.info = env->GetStaticIntField(clazz, env->GetStaticFieldID(clazz, "INFO", "I"));levels.warn = env->GetStaticIntField(clazz, env->GetStaticFieldID(clazz, "WARN", "I"));levels.error = env->GetStaticIntField(clazz, env->GetStaticFieldID(clazz, "ERROR", "I"));levels.assert = env->GetStaticIntField(clazz, env->GetStaticFieldID(clazz, "ASSERT", "I"));return AndroidRuntime::registerNativeMethods(env, "android/util/Log", gMethods, NELEM(gMethods));}register_android_util_Log函数向java.util.Log类中注册了gMethods中的两个方法：isLoggable和println_native。但是当我打开eclipse时，查看Log类中的源码并没有这两个类，我又用了jd-jui打开了Android SDK中4.4的jar包，发现了native方法isLoggable，但是依旧没有发现println_native方法，我猜测Android SDK中的类和方法毕竟是不全的！
结语：还有很多地方没有分析到，比如dalvik虚拟机参数的分析、dvmStartup函数中大量初始化函数的功能等。
每天告诉自己一次，『我真的很不错』
