null pointer exceptions

import java.util.*; public class employee { static int ch; static int emp[]; String name; int id,age; float sal; void insert() { employee[] emp=new employee[90];

    Scanner r=new Scanner(System.in);
    System.out.println("Enter the no of employees");
    int n=r.nextInt();
    for(int i=0;i<n;i++)
    {
        System.out.println("Enter details of employee"+(i+1));
        emp[i].setdata();
    }
    System.out.println("---------------------details of employee-----------------------\n");
    System.out.println("name \t id \t age \t salary");



    for(int i=0;i<n;i++)

    {

        emp[i].getdata();
    }

}
private void setdata() {
    Scanner sc=new Scanner(System.in);
    System.out.println("Enter the name of employees");
    name=sc.nextLine();
    System.out.println("Enter the id of employees");
    id=sc.nextInt();
    System.out.println("Enter the id of employees");
    age=sc.nextInt();
    System.out.println("Enter the salary of employees");
    sal=sc.nextFloat();
}
private void getdata() {

    System.out.println(name+"\t"+id+"\t"+age+"\t"+sal);
}

void search()
{
    System.out.println("searched");
}
void delete()
{
    System.out.println("deleted");
}
void edit()
{
    System.out.println("edited");
}
public static void main(String[] args) {
    // TODO Auto-generated method stub
    employee e=new employee();
    Scanner s=new Scanner(System.in);
    System.out.println("Enter your Choice:");
    System.out.println("1.Insert\n2.Search\n3.Delete\n4.Edit");
    System.out.println("Enter your Choice:");
    ch=s.nextInt();
    switch(ch)
    {
    case 1:
        e.insert();
        break;
    case 2:
        e.search();
        break;
    case 3:
        e.delete();
        break;
    case 4:
        e.edit();
        break;
    case 5:
        System.out.println("Wrong choice entered");

    }

}

} Exception in thread "main" java.lang.NullPointerException at employee.insert(employee.java:19) at employee.main(employee.java:73) please sort it out