Occasionally when working with Java classes in ColdFusion MX gold you receive an error message, java.lang.IllegalAccessException. Why did you receive this when the method you’re calling is public? Why do we care since it’s been fixed in ColdFusion MX 6.1?

The answer to the first question leads into the second–exploring these issues helps us learn more about how ColdFusion MX works.

When you write code in ColdFusion that utilizes Java classes, the code often looks a lot like real Java. In many cases, you can actually copy simple Java code into CFScript and make it run with just a few minor changes. So how does this code differ in from real Java code in the final CFMX generated classes and why did we sometimes get java.lang.IllegalAccessException?

Even though CFML compiles down to Java, CF variables are not strongly typed and as such code that operates on these variables can not be converted directly to traditional Java method calls. Instead CFMX produces code that utilizes reflection to make the calls you specified in CFML.

Sometimes when using reflection the Java runtime won’t recognize the method call as having the necessary priviledges and generates an access exception. However, if the reflection context has sufficient privledges, then you can use the AccessibleObject functionality to tell the reflector to ignore security checks on the taget method.

ColdFusion MX 6.1 now does this for all Java calls which resolves the error message. I want to thank the CFMX team for all the fixes in CFMX 6.1 and for their great technical support and explanations, including this one, during the beta.