/**
     * Initializes a Thread.
     *
     * @param g the Thread group
     * @param target the object whose run() method gets called
     * @param name the name of the new Thread
     * @param stackSize the desired stack size for the new thread, or
     *        zero to indicate that this parameter is to be ignored.
     */

    private void init(ThreadGroup g, Runnable target, String name,
                      long stackSize) {

  {- -------------------------------------------
  (1) 引数が null だったら, NullPointerException.
      ---------------------------------------- -}

            if (name == null) {
                throw new NullPointerException("name cannot be null");
            }

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

            Thread parent = currentThread();

  {- -------------------------------------------
  (1) 
      ---------------------------------------- -}

            SecurityManager security = System.getSecurityManager();
            if (g == null) {
                /* Determine if it's an applet or not */

                /* If there is a security manager, ask the security manager
                   what to do. */
                if (security != null) {
                    g = security.getThreadGroup();
                }

                /* If the security doesn't have a strong opinion of the matter
                   use the parent thread group. */
                if (g == null) {
                    g = parent.getThreadGroup();
                }
            }

            /* checkAccess regardless of whether or not threadgroup is
               explicitly passed in. */
            g.checkAccess();

            /*
             * Do we have the required permissions?
             */
            if (security != null) {
                if (isCCLOverridden(getClass())) {
                    security.checkPermission(SUBCLASS_IMPLEMENTATION_PERMISSION);
                }
            }

  {- -------------------------------------------
  (1) java.lang.ThreadGroup.addUnstarted() を呼び出し, 
      ---------------------------------------- -}

            g.addUnstarted();

  {- -------------------------------------------
  (1) フィールドの初期化を行う
      ---------------------------------------- -}

            this.group = g;
            this.daemon = parent.isDaemon();
            this.priority = parent.getPriority();
            this.name = name.toCharArray();
            if (security == null || isCCLOverridden(parent.getClass()))
                this.contextClassLoader = parent.getContextClassLoader();
            else
                this.contextClassLoader = parent.contextClassLoader;
            this.inheritedAccessControlContext = AccessController.getContext();
            this.target = target;
            setPriority(priority);
            if (parent.inheritableThreadLocals != null)
                this.inheritableThreadLocals =
                    ThreadLocal.createInheritedMap(parent.inheritableThreadLocals);
            /* Stash the specified stack size in case the VM cares */
            this.stackSize = stackSize;

            /* Set thread ID */
            tid = nextThreadID();
        }