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2.5. An Object Oriented Class Example

Let’s create a class where each object of the class represents a person. Every person has a name and a cell phone number which we will store in String variables. A string is a sequence of characters like in “Hello”. We can store the name and cell phone number in fields in a Person object. We provide methods to get and set the data. We provide a constructor to initialize the data when the object is first created.

Go ahead and click the button to see what gets printed.

public class Person { /// fields //////////////// private String name; private String cell; /////// constructors //////////////////// public Person(String theName, String theCell) { this.name = theName; this.cell = theCell; } //////////// methods /////////////////////// public String getName() { return this.name; } public void setName(String theName) { this.name = theName; } public String getCell() { return this.cell; } public void setCell(String theCell) { this.cell = theCell; } public String toString() { return "name: " + this.name + ", cell: " + this.cell; } //////////// main for testing ////////////// public static void main(String[] args) { Person p1 = new Person("Deja", "555 132-3253"); System.out.println(p1); Person p2 = new Person("Avery", "555 132-6632"); System.out.println(p2); } }

Note

A class declaration typically starts with public then class then the name of the class. The body of the class is defined inside a { and a }.

Check Your Understanding

A person’s name can actually be broken into parts. We can create a name class to handle this.

2-5-2: Click on the class declaration (not the body of the class) in the following class definition. Then click the "Check Me" button to see if you are correct or not.The class declaration starts the class. It contains the keyword class in it.

public class Name {

    private String first;
    private String last;

    public Name(String theFirst, String theLast)
        first = theFirst;
        last = theLast;
     }

     public void setFirst(String theFirst)
        first = theFirst;
     }

     public void setLast(String theLast)
        first = theLast;
     }

}

2-5-3: Click on the class declaration (not the body of the class) in the following class definition. Then click the "Check Me" button to see if you are correct or not.The class declaration starts the class. It contains the keyword class in it.

public class PhoneNumber {

    private String country;
    private String areaCode
    private String number

    public PhoneNumber(String theCountry, theArea, theNumber)
        country = theCountry;
        areaCode = theArea;
        number = theNumber;
     }

     public String getNumber() {
        return number;


     public void setNumber(String theNumber)
        number = theNumber;
     }

}

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