Null pointer exception in getter method

Question

I am trying to have a getter method that returns a collection. The method is supposed to get a list of files from a directory and returns the collection. I am instantiating the List in the method and the converting an array into the List using asList. Then I am trying to return the list to the main method.
When I put this code in the main method I get the result I want, but when I try to put it in the getter method and call it from main I get a NullPointerException compile error.
I need help understanding what I am doing wrong when I move this code out of the main method and into another non static method.

Answer 1

I was looking around at other posts and noticed they
give more code than I was. I was trying to save you
some reading but now I see I just made it harder.No problem. It can be difficult to know just how much code to post to get all the relevant stuff but not a bunch of extraneous junk.
The problem is you have two different currentDirectory variables. The member variable (declared just inside public class FileBrowser and a method (or "local") variable declared in main. The local one in main hides or shadows (those two terms are similar in Java, and I forget the details of which is which) the member variable.
When you set the one in main, it doesn't affect the member variable. The local one in main only exists inside of main.
To fix this, change this line inside of main: File currentDirectory = new File(System.getProperty("user.dir")); to this: currentDirectory = new File(System.getProperty("user.dir")); By having the class name File there you're declaring a new variable. Without the class name, you're just using the existing member variable.