Accessing a static variable via an object reference in Java

Question

Why can we access a static variable via an object reference in Java, like the code below?

public class Static {
    private static String x = \"Static variab         


        

Answer 1

The reason that it is allowed is that the JLS says it is. The specific sections that allows this are JLS 6.5.6.2 (for the member.x cases) and JLS 15.11.1 (in both cases). The latter says:

If the field is static:

• If the field is a non-blank final field, then the result is the value of the specified class variable in the class or interface that is the type of the Primary expression.

• If the field is not final, or is a blank final and the field access occurs in a class variable initializer (§8.3.2) or static initializer (§8.7), then the result is a variable, namely, the specified class variable in the class that is the type of the Primary expression.

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Why are these allowed by the JLS?

Frankly, I don't know. I can't think of any good reasons to allow them.

Either way, using a reference or this to access a static variable is a bad idea because most programmers are likely to be mislead into thinking that you are using an instance field. That is a strong reason to not use this feature of Java.

In your first and second cases you should reference the variable as x or Static.x rather than member.x. (I prefer Static.x.)