Question

The scope rules of modern programming languages are rooted in rules developed by the earliest block structured languages like Algol. Adding object orientation to languages adds one more layer of complexity to this issue.

Let's consider Java, a language with which everyone should be familiar, and explore its scope rules. One aspect of the scope rules of any language is when data or methods can have the same name. Give examples in Java to illustrate a case where declaring two local variables with the same name in same method is permitted and one where it is prohibited. Are the rules governing redeclaration of local names the same as those governing redeclaring local names that rename class-level names?

One consequence of scope rules in most languages is that forward references (referring to names before they are declared) are prohibited. Are such forward references always prohibited within a single Java class? Are forward references of local names always prohibited within a single method?

Answer 1