soapgateway is a software element for the integration of clients and servers in a SOA environment. Roughly, it redirectes SOAP requests targeted to it, to the real webservers that offer the services, applying load-balance and authentication policies
The JProgress project provides tools for connectivity with Java clients and the Progress database. JProgress provides an n-tier software architecture for database access for executing remote requests over WANs and the Internet.
NetComm4j is a java communication API to create client server applications where clients can make requests to a server and wait for responses. It also provides an event mechanism to enable clients to receive asynchronous messages from server.