Specify order of signature-related trailer fields

Field 93 is SignatureLength, Field 89 is Signature. The fields 89 and 93 are in the trailer. 89 is DataField. 93 is the length of 89. When receives a message containing field 89, accptor will extract every field in order. 89 is extracted earlier. Acceptor cannot find the length of it(93) at this time. So exception occurs.

A effective method is to change the order of message. Put the field 93 former to the field 89. Thus, the field 93 is extracted earlier than 89. Use this method:
Message.Trailer.calculateString():
super.calculateString( buffer, new int[]

, new int[]

);