1. A method for delivering an agent on a machine, comprising: compiling at a machine an agent class for an agent, the agent monitor a distributed business transaction on the machine once the agent is loaded in a Java virtual machine; loading an interface definition to be implemented by the agent on the machine, wherein the interface definition is bootstrap loaded onto the Java virtual machine at startup time; analyzing the agent class intended to implement an interface complying with the interface definition; and modifying the agent class to comply with the interface definition to be implemented by the agent when the loaded agent monitors the distributed business transaction.