IMS message-processing applications must do all message processing and transaction synchronization either in COBOL or Java, rather than distributing this logic between application components written in both languages.
COBOL components use CALL statements to DL/I services to process messages (GU and GN) and synchronize transactions (CHKP). Java components use IMS Java classes to do these functions. You can use object instances of classes derived from IMSFieldMessage to communicate entire IMS messages between the COBOL and Java components of the application.