Fix documentation for Parcel.readException().

The old documentation was kind of useless and not clear, so this is an
improvement.

In addition to this change, I think this method should probably be private
instead of public, especially since the values for code are private. But it's
too late to change that now. Also the method name is pretty poor, since it's
not actually reading anything. Something like "throwException" would be more
appropriate.

I'm open to suggestions on how to improve this situation. Maybe mark the
method as deprecated with a comment that it will be made private in the
future?

Change-Id: I830f2bcf606714bd130d8c953aa33974b33c9a83
diff --git a/core/java/android/os/Parcel.java b/core/java/android/os/Parcel.java
index 94b9617..51e46bc 100644
--- a/core/java/android/os/Parcel.java
+++ b/core/java/android/os/Parcel.java
@@ -1454,10 +1454,11 @@
     }
 
     /**
-     * Use this function for customized exception handling.
-     * customized method call this method for all unknown case
-     * @param code exception code
-     * @param msg exception message
+     * Throw an exception with the given message. Not intended for use
+     * outside the Parcel class.
+     *
+     * @param code Used to determine which exception class to throw.
+     * @param msg The exception message.
      */
     public final void readException(int code, String msg) {
         switch (code) {