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Association is relation between two separate classes which establishes through their Objects. Association can be one-to-one, one-to-many, many-to-one, many-to-many.

In Object-Oriented programming, an Object communicates to other Object to use functionality and services provided by that object.
Composition and Aggregation are the two forms of association.

  • Example of Association

    Let us see the example of Association relationship .


    Create Bank class

    // class bank
    class Bank 
    {
        private String name;
         
        // bank name
        Bank(String name)
        {
            this.name = name;
        }
         
        public String getBankName()
        {
            return this.name;
        }
    } 


    Create Employee class

    
    // employee class 
    class Employee
    {
        private String name;
         
        // employee name 
        Employee(String name) 
        {
            this.name = name;
        }
         
        public String getEmployeeName()
        {
            return this.name;
        } 
    }


    Association between both the classes in main method.

    
    class Example
    {
        public static void main (String[] args) 
        {
            Bank bank = new Bank("Axis");
            Employee emp = new Employee("Durgesh");
             
            System.out.println(emp.getEmployeeName() + 
                   " is employee of " + bank.getBankName());
        }
    }

    Output:
    Durgesh is employee of Axis

    In above example two separate classes Bank and Employee are associated through their Objects. Bank can have many employees, So it is a one-to-many relationship.

What next?

The next topic is Aggregation in Java

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