1. An Introduction to Java – Part II
Ben Lerner
An Introduction to Java – Part II

2. Class Definitions Classes consist of constructors, methods, and fields
<modifier> class Person {
constructors
fields
methods }

3. Constructors and Objects
Constructors initialize objects, same name as the class
public Person (string name, int age)
{ … }
Objects created using new keyword and the constructor, store reference
Person P = new Person(“Michael”, 21);

4. Fields Fields are the variables that define the attributes of a class
string name_; int age_;
Constructors initialize an object’s fields
public Person (string name, int age) {
name_ = name; age_ = age; }

5. Methods Mutator methods change fields void setAge(int a) { age_ = a; }
Inspector methods access fields
string getName()
{ return name;}
Constructors are also methods

6. Parameters
Both primitive variables and objects can be passed to methods
Parameters are always passed by value
Remember that objects in Java are just references to the objects