How do i call a method that calls a method?

[Daniel Hoang]

I have a Person class, a Name class, and a demo. What i need is to call a method from the Person class that calls a method from the Name class for the demo. Heres an example:

public class Person 
private Name Name;
{
public String getFirstName() {
	return Name.getFirstName(); //I know this doesnt work, i get a nullpointer
}

public class Name //Im supposed to call the methods from this class from Person class
{
private String firstName;
}
public String getFirstName(){
	return firstName;
}

public class PersonTester { //This is the demo the teacher provides
		Person newPerson = new Person();
		//class read methods
		System.out.println("Please enter a complete name and age "
		   + "in the following format. \nFirstname Middlename Lastname age");
		getName(newPerson);
		newPerson.read();
		Person myPerson = new Person(newPerson.getFirstName(),
		   newPerson.getMiddleName(), newPerson.getLastName(),
		   newPerson.getAge());

[Jeanne Boyarsky]

Daniel,
Consider changing

private Name Name;

to

private Name name;

Java starts variables with lower case letters. Which makes it clearer whether you are using the class Name or the variable name.

You are getting the NullPointer because Person never instantiates name. You want to create a setter in the Person class like public void setName(Name n) { name = n): }. Then your tester class can pass in a Name object.

[Daniel Hoang]

Oh yeah, i didnt include that in my code example, oops. While i do have a set method, im trying a couple ways shown below, but still get a nullpointer. What else am i missing?

public Person(String firstName, String middleName, String lastName, int age) {
	firstName = "";
	middleName = "";
	lastName = "";
	age = 0;

public void setFirstName(String newFirstName){
	Name.setFirstName(newFirstName);

// or

public void setFirstName(String newFirstName){
       Name.firstName = newFirstName;

[Jeanne Boyarsky]

You've succeeded in moving the NullPointer to your set method. But Person still doesn't instantiate Name. So it is null when you try to update it in the setter. You need to call new Name() in the Person constructor.

[Daniel Hoang]

I dont think im allowed to edit the demo

[Winston Gutkowski]

Daniel Hoang wrote:Heres an example:

Daniel,

Please DontWriteLongLines. It makes your threads very hard to read. I've broken your up this time.
Remember the rule: 80 charcters max.

Thanks

Winston