BOOTCLASSPATH 不添加jar包路径，，系统启动后将无法找到自定义JAVA层系统服务的相关类，这是由于自定义系统服务jar包是Dalvik所需的基本库文件。如果不添加相关路径会报如下错误：
W/dalvikvm( 2582): Unable to resolve superclass of Lcom/android/server/yourdir/yourService; (1633)W/dalvikvm( 2582): Link of class ‘Lcom/android/server/yourdir/yourService;’ failedD/dalvikvm( 2582): DexOpt: unable to opt direct call 0x276b at 0x258 in Lcom/android/server/ServerThread;.run
三篇必看原理文章：
Android 类实现探索-系统基础类
Dalvik 分析之准备篇
Dalvik 分析 – Class加载篇
init.rc:export BOOTCLASSPATH /system/framework/core.jar:/system/framework/bouncycastle.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/core-junit.jarBOOTCLASSPATH=/ango/system/framework/core.jar:/ango/system/framework/bouncycastle.jar:/ango/system/framework/ext.jar:/ango/system/framework/framework.jar:/ango/system/framework/android.policy.jar:/ango/system/framework/services.jar:/ango/system/framework/core-junit.jard:/linux/linuxkernel/WORKING_DIRECTORY/android-omap-20111108-gingerbread/dalvik/vm/Init.c//getenv of classpath and BOOTCLASSPATH configed by init.rcstatic void setCommandLineDefaults()putenv("BOOTCLASSPATH=/ango/system/framework/core.jar:/ango/system/framework/bouncycastle.jar:/ango/system/framework/ext.jar:/ango/system/framework/framework.jar:/ango/system/framework/android.policy.jar:/ango/system/framework/services.jar:/ango/system/framework/core-junit.jar"); envStr = getenv("BOOTCLASSPATH"); if (envStr != NULL) gDvm.bootClassPathStr = strdup(envStr); else gDvm.bootClassPathStr = strdup(".");d:/linux/linuxkernel/WORKING_DIRECTORY/android-omap-20111108-gingerbread/dalvik/vm/oo/Class.c/** Prepare a ClassPathEntry struct, which at this point only has a valid* filename. We need to figure out what kind of file it is, and for* everything other than directories we need to open it up and see* what’s inside.*/static bool prepareCpe(ClassPathEntry* cpe, bool isBootstrap)/** Convert a colon-separated list of directories, Zip files, and DEX files* into an array of ClassPathEntry structs.** During normal startup we fail if there are no entries, because we won’t* get very far without the basic language support classes, but if we’re* optimizing a DEX file we allow it.** If entries are added or removed from the bootstrap class path, the* dependencies in the DEX files will break, and everything except the* very first entry will need to be regenerated.*/static ClassPathEntry* processClassPath(const char* pathStr, bool isBootstrap)/** Initialize the bootstrap class loader.** Call this after the bootclasspath string has been finalized.*/bool dvmClassStartup(void)
以诚感人者，人亦诚而应。
