Defining a Class in Java

User.java

class User {                                                      //(D)
    private String name;
    private int age;
    
    public User( String str, int yy ) { name = str;  age = yy; } 
    public void print() { 
        System.out.println( "name: " + name + "  age: " + age ); 
  }
}

class Test {                                                      //(E)
    public static void main( String[] args ) {
        User u = new User("Zaphod", 23 );
        u.print();
    }
}

User2.java

This modification includes a static main method in the User class definition. This practice is a simple way of including small test programs in source programs.

Now we can enter:


javac User2.java
java User2

Notice that we had to rename the class from User to User2 and rename the constructor to User2

class User2 {
    private String name;
    private int age;
    
    public User2( String str, int yy ) { name = str;  age = yy; } 
    public void print() { 
        System.out.println( "name: " + name + "  age: " + age ); 
  }
    public static void main( String[] args ) {
        User u = new User("Zaphod", 23 );
        u.print();
    }
}


Maintained by John Loomis, last updated 4 March 2004