Methods

Question 1

What is the difference between a method and a function? Is there one?

Answer 1

A method, like a function, is a set of instructions that perform a task. The difference is that a method is associated with an object, while a function is not.

Question 2

How do I designate a method’s inputs?

Answer 2

Put them in the parameters.

Question 3

How do I designate a method’s outputs?

Answer 3

You just put them in the method signature instead of the word void.

Question 4

Where can a method definition go in your source code? Can definitions be nested?

Question 5

Where can a method call go in your source code? Can calls be nested?

Question 6

How many things can a method return? (How many types?)

Answer 6

You can return only one value in Java. If needed you can return multiple values using array or an object. Methods can only return one type.

Question 7

How do I return several things from a method?

Question 8

What if I have nothing to return?

Answer 8

void keyword

Question 9

How many return statements are allowed in a method?

Answer 9

You can have several, but it’s best to keep the code clean and clear.

Question 10

What is the ideal length for a method?

Answer 10

5-10 lines

Question 11

Can a method call itself?

Answer 11

Yes, when a method calls itself, it is called recursion.

Question 12

What is the difference between a static and non-static method? Give an example of each.

Answer 12

Non-static methods have access to fields. Static methods don’t.

One way to think about it is that static methods are just independent methods with no context. They’re defined in a class, but they’re not part of an individual object.

Non-static methods can’t be executed independently. They’re part of an object. They have access to an object’s state.

Non-static methods are executed using an instance of an object. Static methods are executed using a class name.

Static method ex:
String.format
String.format(“Numbers: %s, %s, %s”, 1, 2, 3);

Non-static method ex: toUpperCase
String vegetable = “kale”;
vegetable.toUpperCase();

Question 13

How do I indicate a method is non-static?

Answer 13

Omit the word static

Question 14

Is this valid syntax?:
void doNothing() {
    return;
}

Question 15

What is method overriding?

Answer 15

In addition to inheriting parent members, subclasses can completely replace a parent method. This is called overriding a method. To override, the method is re-implemented in the subclass

Question 16

What is method overloading and when is it useful?

Answer 16

If methods have the same name, but different signatures, they are said to be overloaded.

Use it when you actually do need multiple methods with different parameters, but the methods do the same thing.

Question 17

Write a method that takes two integers and returns their average as an integer, rounded down.

Change it to return their average rounded up.

Question 18

Is it possible to write a method that accepts a variable number of parameters without method overloading?