Integer.getInteger and Integer.valueOf in java

IntegerOrString.java

public class IntegerOrString {
 
       public static void main(String[] args) {
             String object1 = "S124";
             String object2 = "124-ab45";
             String object3 = "124";
             
             int result1, result2, result3;
             
             /* public static Integer getInteger(String nm) */
             /* Determines the integer value of the system property with the specified name. */
             
             result1 = Integer.getInteger(object1); // NullPointerException
             result2 = Integer.getInteger(object2); // NullPointerException
             result3 = Integer.getInteger(object3); // NullPointerException
             
             System.out.println("result1" + result1);
             System.out.println("result2" + result2);
             System.out.println("result3" + result3);
             
             System.out.println("object1: " + Integer.getInteger(object1));
             System.out.println("object2: " + Integer.getInteger(object2));
             System.out.println("object3: " + Integer.getInteger(object3));
             
             /* public static Integer valueOf(String s) throws NumberFormatException */
             /* Returns an Integer object holding the value of the specified String. */
             
             result1 = Integer.valueOf(object1); // NumberFormatException
             result2 = Integer.valueOf(object2); // NumberFormatException
             result3 = Integer.valueOf(object3);
             
             System.out.println("r3: " + result3);
             
             System.out.println("\n[ READ MORE ]\n\n[ https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html ]");
       }
 
}

Please comment on lines 13 - 19. and 28 + 29
Otherwise, throw exception