Methods are one of the major structuring mechanisms for Java programs.
Every method must return a value.
A program can only use methods that are declared in its own class.
A method cannot make changes to its actual parameters.
A method cannot make changes to its formal parameters.
A formal parameter behaves as an initialised local variable.
A method should always perform one well-defined task.
One can always compose two methods together.
Variables should always be declared as locally as possible.
It is not possible to have two methods with the same name in the same class.