(If you don’t have an instance of a String, it doesn’t make sense to call length.) That doesn’t make sense, does it? length is a method in the String class (technically an “instance method”), and it’s only available when you have an instance of a String, such as name. That’s an attempt to call length as a static method. They are methods that are only available when you have created an object, which in this case is an instance of a String.)Īs an important point, note that you don’t write code like this: (Nobody uses the term “object methods,” but it may be helpful to think of them that way at this time. The name instance has methods available to it like charAt, length, split, etc., and these are called instance methods. Name is an instance of a String (what we also call an object). For example, if you create an instance of a String, like this: Instance members are variables and methods that you can only access when you have an instance of a class. Static members can be accessed directly on the class (you don’t need an instance of a class to refer to static members).Instance members belong to an instance of a class (what we call an object).Instance methods vs static methodsĪ short answer goes like this: In Java you have instance members (variables and methods) and static members:
If you’ve ever seen a Java compiler error message like “Cannot make a static reference to the non-static method doFoo,” or “Cannot make a static reference to the non-static field foo,” here’s a quick explanation of these messages.
Java FAQ: What does the Java error message “Cannot make a static reference to the non-static method/field” mean? A $2 donation will help keep this site running!
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