DateFormat.java (format): Throw IllegalArgumentException if j' is not a Number or Date instance.

* java/text/DateFormat.java (format): Throw IllegalArgumentException
	if j' is not a Number or Date instance.
	* java/text/SimpleDateFormat.java (tokens): Make it an ArrayList
	instead of Vector.

From-SVN: r71871

libjava/java/text/DateFormat.java

@@ -151,6 +151,8 @@ public abstract class DateFormat extends Format implements Cloneable
   {
     if (obj instanceof Number)
       obj = new Date(((Number) obj).longValue());
+    else if (! (obj instanceof Date))
+      throw new IllegalArgumentException ("Cannot format given Object as a Date");
     return format ((Date) obj, buf, pos);
   }