Receiving null pointer exception when calling a method of the object

Question

class Employee {
     private String name;
     private int age;
     private double salary;
     private String dob;
     public void setEmp(String name, int age, double salary, String dob){ //setter method
          this.name = name;
          this.age = age;
          this.salary = salary;
          this.dob = dob;
     public Employee getEmp(){ //getter method
          return this;
public class EmployeeDemo {
     public static void main(String[] args) {
          String str1 = "John_Stone251000.0005051975";
          String str2 = "Jane Doe  242000.0006071980";
          String str3 = "Will Smith356000.5005051960";
          String[] str = {str1,str2,str3};
          Employee[] emp = new Employee[3];
          String emp_name, emp_dob;
          int emp_age;
          double emp_sal;
          for(int i=0;i<str.length;i++){
               emp_name=str.substring(0,10);
               emp_age=Integer.parseInt(str[i].substring(10,12));
               emp_sal=Double.parseDouble(str[i].substring(12,19));
               emp_dob=str[i].substring(19,26);
               emp[i].setEmp(emp_name,emp_age,emp_sal,emp_dob); //NullPointerException error
After compiling both classes and running:
output error: Exception in thread "main" java.lang.NullPointerException
        at EmployeeDemo.main(EmployeeDemo.java:21)I don't understand why I am getting the NullPointerException error and how to fix it?

Answer 1

I expect the following program to output the String "Victor Shakapopulis":
public class Test
  public static void main (String[] args)
    String[] data = new String[3];
    System.out.println(data[0]);
}Will it? Or will the program output the String "hello world". If neither of those, what will the program output?
Have the program output data[1] and data[2] as well. What can you conclude about the contents of an array after you create it?