Java - getting error on Hashmap.put

Question

I wrote a simple program in JAVA having 4 classes:

Main - > CarFaxApp

GUI / Logic - > CarFaxFrame

Object -> Car

Validator -> CarFaxValidator

Once the program is running and I start to enter the necessary data in the textbox's for the car (String vin, String make, String model, int year). Everything works fine, but when I hit buttonADD(), I get a error.

private HashMap<String,Car>hmCar; //Hashmap to hold Cars, the key pair value consists of (Vin, Car Object)

The error happens on hmCar.put(car.getVin(), car); which I dont understand why, I tried debugging up to the point and car does hold the correct values.

Here a screen shot of the error:

enter image description here

@PM77-1 Yes hmCar could be null at this point, but why would this matter if its a hashmap()? — Joshua Dalley, Mar 14 '15 at 01:29
You cannot call a method on `null` object. This will **always** produce NPE. — PM 77-1, Mar 14 '15 at 01:36
@PM77-1 The problem was my hashmap was still null and was never initialized as a new hashmap. — Joshua Dalley, Mar 14 '15 at 01:55

score 2 · Answer 1 · answered Mar 14 '15 at 01:54

2

the error is NullPointException, are you sure you do this hmCar = new HashMap<String, Car>(); before you put the entry in.

answered Mar 14 '15 at 01:54

Wednesday

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Java - getting error on Hashmap.put

1 Answers1