why do we need super keyword in java code example

Example 1: super keyword in java

Variables and methods of super class can
be overridden in subclass. 
In case of overriding , a subclass
object call its own variables and methods.
Subclass cannot  access the variables and
methods of superclass because the overridden
variables or methods hides the 
methods and variables of super class.
But still java provides a way to access 
super class members even if 
its members are overridden. Super is
used to access superclass variables, methods, constructors.
Super can be used in two forms :
1) First form is for calling super class constructor.
2) Second one is to call super class variables,methods.
Super if present must be the first statement.

Example 2: super keyword in java

// example on super keyword in java
class Manager
{
   int salary = 50000;
}
class Employee extends Manager
{
   int salary = 20000;
   void display(int salary)
   {
      // here refers to the parent class instance variable
      System.out.println(super.salary);
   }
   public static void main(String[] args)
   {
      Employee obj = new Employee();
      obj.display(30000);
   }
}