Android init.rc BOOTCLASSPATH

 BOOTCLASSPATH 不添加jar包路徑，系統啟動後將無法找到自訂JAVA層系統服務的相關類，這是由於自訂系統服務jar包是Dalvik所需的基本庫檔案。如果不添加相關路徑會報如下錯誤：

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;' failed
D/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
類實現探索-系統基礎類

Dalvik 分析之準備篇

Dalvik 分析 - Class載入篇

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.jar
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

d:/linux/linuxkernel/WORKING_DIRECTORY/android-omap-20111108-gingerbread/dalvik/vm/Init.c
//getenv of classpath and BOOTCLASSPATH configed by init.rc
static 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)