Question

I’ve noticed that when doing the length of an array you write something like:

arrayone.length;

However, for such things as array lists or a string, you write a bracket on the end, such as the following for the length of the String:

stringone.length();

What is the key reason for this and how do you know when to put the brackets or now?

Answer 1

.length;

directly accesses a field member.

.length();

invokes a method (i.e. an accessor) to access a field member.

in the case of String, this is to be expected since it’s immutable.