The Object Constraint Language OCL is a textual specification language that could be used for constraining the modelling elements that occur in UML diagrams. Typical constraints include class invariants and preconditions and postconditions of operations. The Java Modelling Language (JML) is a behavioural interface specification language designed for specifying Java classes and interfaces. This paper defines a translation of OCL expressions and constraints into the Java Modelling Language. The objective of this translation is to be able to map UML object-oriented designs with OCL constraints to Java classes and interfaces annotated with JML specifications, and to carry out logical reasoning about such classes and interfaces using JML tools which include a run time assertion checker and an interactive prover based on PVS.