Question

what do classes use to define their behavior?
is it constructors? variables? parameters? something else? can someone please explain?

Answer 1

this is in Java btw!!!

Answer 2

All of the above. First, classes are descriptions ( blueprints ) for objects to be created. The constructor method initializes ( sets up ) the object for use. The behavior of an object would be primarily influenced by it's methods ( functions bound to the object ), but also what attributes ( methods would be an attribute, but attribute usually used as a term of variables ) the object has.

Basically, methods are verbs and attributes are nouns. An object possesses attributes and can do methods with them and parameters passed to it.