Type Values

Since the Expression Language has two basic types (primitive and reference), it also has two kinds of data values that can be stored in variables, passed as arguments, returned by methods, and operated on: primitive and reference values.

There is also a special null type, the type of the null expression, which has no name. Because the null type has no name, it is impossible to declare a variable of the null type or to cast to the null type. The null reference is the only possible value of an expression of null type. The null reference can always be cast to any reference type. In practice, you can ignore the null type and consider that null is merely a special literal that can be of any reference type.

This section includes the following topics: