"Comparison method violates its general contract!"
This issue suddenly popped out today where I'm getting above error in all Web Service Execution Step of my existing project. I get the same error even if I add a WSDL to any Web Service Execution Step in a new test case in my existing project.
But I'm able to add the same WSDL to a new project and it works just fine.
I had around 50 test cases and all Web Service Execution step stopped working in a flash.