Unable to load class that supports TCP/IP

If Java attempts to use class files from the local file system, this contravenes security rules and generates an exception.


The following error occurs when running applications:

java.io.IOException: CTG6664E Protocol tcp not supported

Probable cause

You are using a Web browser and CICS® Transaction Gateway on the same workstation, and the ctgclient.jar and ctgserver.jar are referenced in the CLASSPATH setting.

Java searches the CLASSPATH environment variable before downloading classes across the network. If the required class is local, Java attempts to use it. However, use of class files from the local file system contravenes the application security rules, and generates an exception.


Edit the CLASSPATH setting to remove ctgclient.jar and ctgserver.jar.