Thread: overloaded consctructors

The constructor for a given class is always the name of the class. Overloading just means that each constructor has different numbers and/or types of arguments. But the name for each overloaded constructor is the same.

Regards,
Jim

I'm not certain what you mean by a "main called Date." I will assume you mean you are using the Date class. And your class will be called DateTest (since that is the name of your constructor).

If you want to use the SimpleDateFormat class you will need to import it or you can just reference it by its full package name (which can get cumbersome).

Note that it is not necessary to call constructors if you just want to write some code to check out something in the main() method. Unless you need to make use of instance fields or methods defined in your DateTest class you don't really need a constructor.

Note: SimpleDateFormat is in java.text, not java.util.

Regards,
Jim

The constructor is directly inside the class. In most cases the constructor is invoked in main and then used to access other instance methods and fields. Here is an example:

public class Foo {
     int value;
     public Foo(int v) {
          value = v;
     }
 
     public static void main(String[] args) {
           Foo foo = new Foo(10);
           foo.start();
     }
 
     public void start() {
           System.out.println(value);  // prints 10
     }
}

If I wanted to print out "value" from the static main method I would have to qualify it with the foo reference.

System.out.println(foo.value);

Regards,
Jim

I just realized that I didn't really address overloaded constructors. Here is a simple example:

public class Person {
      String name;
      int age;
 
      public Person(String name, int age) {
            this.name = name;
            this.age = age;
       }
 
       public Person(String name) {
             // call other constructor with this name and 33
             this(name, 33);  // default age of 33
       }
 
       public static void main(String args[]) {
              Person p1 = new Person("Bob", 22);
              System.out.println(p1);  // should print "Bob 22"
 
              Person p2 = new Person("Sue");
              System.out.println(p2);  // should print "Sue 33"
       }
 
       public String toString() {
           return name + " " + age;
       }
}

Regards,
Jim