The document provides an overview of Java constructors, including their definition, types (default and parameterized), and notable features such as constructor overloading. It contrasts constructors with methods, noting key differences in usage and naming conventions. Additionally, various training topics and courses offered by Quontra Solutions, including programming, data warehousing, and networking, are listed.

1. Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk
Quontra Solutions
by
Java Constructors

2. Constructor
• Constructor in java is a special type of method that is used to
initialize the object
• Java Constructor is invoked at the time of object creation
• They do not contain any return type
• Constructor name is same as class name
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

3. Types of Constructors
• Default constructor (no-arg constructor)
• Parameterized constructor
Types of constructors
Default constructor Parameterized constructor
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

4. Default Constructors
Example for default constructor:
class Cons{
cons(){
System.out.println("constructor is created");
}
public static void main(String args[]){
Cons c=new Cons();
}
}
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

5. Parameterized Constructors
Example for parameterized constructor
class Student4{
int id;
String name;
Student4(int i,String n){
id = i;
name = n; }
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student4 s1 = new Student4(111,"Karan");
Student4 s2 = new Student4(222,"Aryan");
s1.display();
s2.display(); }
}
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

6. Difference between constructor and method
Constructor Method
Constructor is used to
initialize the state of an
object.
Method is used to expose
behaviour of an object.
Constructor must not have
return type
Method must have return
type.
Constructor is invoked
implicitly.
Method is invoked explicitly.
Constructor name must be
same as the class name.
Method name should not
be same as class name
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

7. Constructor Overloading
• Constructors are methods that can be overloaded, just like any other
method in a class.
• Constructors having the same name with different parameter list is
called constructor overloading.
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

8. Topics Covered during Training
• Classes, Objects, Keywords, Methods
• Exception Handling
• String Handling
• Multithearding
• AWT
• Swing
• Applet
• Collections
• Hibernate
• Struts etc………………
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

9. Quontra Solutions Offers:
Data Warehouse
OBIEE, Cognos, Informatica
Microsoft Courses
C# .NET, ASP .NET, VB .NET
& etc….
Programming Courses
Core Java, Adv Java,
J2EE, & etc….
Testing Tools
Manual, QTP, Selenium,
Load Runner
Salesforce CRM
Salesforce CRM, ADMIN,
Developer
Networking Courses
Linux, Unix, Sun Solaris,
CCNA
Mobile Apps
Android, IOS, Cloud
Computing
Data Base
SQL PL/SQL, SQL server
DBA, ORACLE 12C DBA
Other Courses…
Business Analyst, Hadoop,
QlikviewCall : 44 (0)20 3734 1498 / 99, Mail Us:
info@quontrasolutions.co.uk

10. Contact Us
Call: 44 (0)20 3734 1498 / 99
Mail:info@quontrasolutions.co.uk
Visit:www.quontrasolutions.co.uk
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk

11. Follow us
Facebook: https://www.facebook.com/quontrasolutionsuk
Twitter : https://twitter.com/QuontraSolution
Google+: https://plus.google.com/+QuontrasolutionsCoUk
Call : 44 (0)20 3734 1498 / 99, Mail Us: info@quontrasolutions.co.uk