public String getRejectionMessage() {
        return rejectionMessage;
    }
Returns the text to include in a message that will be sent to the sender of the packet
that got rejected or {@code null} if none was defined. If no text was specified then
no message will be sent to the sender of the rejected packet.

@return the text to include in a message that will be sent to the sender of the packet
        that got rejected or {@code null} if none was defined.
xmppserver/src/main/java/org/jivesoftware/openfire/interceptor/PacketRejectedException.java