This paper describes an implementation of resumable and mobile processes for a new process-oriented language called ProcessJ. ProcessJ is based on CSP and the π-calculus; it is structurally very close to occam-π, but the syntax is much closer to the imperative part of Java (with new constructs added for process orientation). One of the targets of ProcessJ is Java bytecode to be executed on the Java Virtual Machine (JVM), and in this paper we describe how to implement the process mobility features of ProcessJ with respect to the Java Virtual Machine. We show how to add functionality to support resumability (and process mobility) by a combination of code rewriting (adding extra code to the generated Java target code), as well as bytecode rewriting.