Java Review

Week 3 - Java Arrays, Objects, Methods

Topics

Control Flow - Loops
References to and Creating Objects
Arrays
Objects - Instances of classes
Java Methods
Introduction to Inheritance

Control Flow

Looping

 for (initialization ; (expression that evaluates to boolean ; increment) {
     ...
  }

  while (expression that evaluates to boolean) {
     ...
  }

  do {
    ...
  } while (expression that evaluates to boolean);

Objects

An object is a software bundle of variables and related methods.
Instances of objects are created using the new keyword.
Results in a reference to an instance of an object.

Arrays

Groups of similar elements, both primitives and object references.

int intArray[] = new int[4]; // elements initially set to 0

CreditCard cards[] = new CreditCard[MAXCARDS];
                  // elements initially set to null

Methods

Instance Methods

methods that are called by referencing an instance of a class

ClassName someObject = new ClassName();
...
someObject.someInstanceMethod( ... );

Class Methods
- Associated with an entire class, not a single instance of a class.
- Identifiable because they are declared static
- Class methods are always callable; there doesn't need to be an instance of the class for you to call class methods on, you just need access to the class and the desired method.
```
ClassName.classMethod( ... );
```

Question: Which one is "better"? Why?