The object-oriented extension of Java c

$${\text{Jav}}{{\text{a}}_\mathcal{O}}$$ extends Java _c to an object-oriented language, supporting the following new features to form expressions: instance fields, instance methods, creation of new instances, method overriding, type casts, type checks and null pointers. Correspondingly execJava _O introduces new rules for expression evaluation and handling of values. In Sect. 5.1 we describe the static and in Sect. 5.2 the dynamic part of the semantics of $${\text{Jav}}{{\text{a}}_\mathcal{O}}$$.