Exception: com.sap.mw.jco.JCO$Exception: (102) RFC_ERROR_COMMUNICATION: Connect to SAP gateway failed Connect_PM...
GWHOST=10.10.10.102, GWSERV=sapgw00, ASHOST=10.10.10.102, SYSNR=00
LOCATION CPIC (TCP/IP) on local host
ERROR max no of 100 conversations exceeded
Cause: The Java application has attempted to make too many concurrent connections to the SAP application server via JCo. This is less an installation exception and more a configuration exception, related to the SAP Web Application server. I include it in this checklist as it is one almost always hit if your application is deployed across a wide user population.
Resolution: Assign additional dialog or service work processes (depending on the type of SAP user the application connects with) through the SAP profile configuration transaction. Alternatively, implement a wait state within the Java application once the number of open threads (concurrent users) has received the maximum (in the above exception the max is 100).
TROUBLESHOOTING JCO EXCEPTIONS
Scenario 1: JCo is unable to find the RFCDSK API library in the system path
Scenario 2: JCo is unable to find the JCORFC library in the system path
Scenario 3: JCo cannot load its RFC middleware layer (3 exceptions)
Scenario 4: JCo finds the wrong version of the librfc library
Scenario 5: JCo exceeds the number of SAP-allocated work processes
Scenario 6: Installing/porting JCo to other operating systems
Review: Conclusion and more resources