getResourceAsStream returns NullpointerException

Question

In Spring, I want to get the image to display on my browser. The image is located in my main project i.e.

> myproject
   - src
   - target
   - img.png

This means that img.png is in the root so I dont supply any path but it returns a NullPointerException. I tried adding the image in src and I changed path to src\img.png but still gave NPE.

Please note, this project is using Maven.

Stack Trace:

java.lang.NullPointerException: null
    at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1792) ~[commons-io-2.4.jar:2.4]
    at org.apache.commons.io.IOUtils.copyLarge(IOUtils.java:1769) ~[commons-io-2.4.jar:2.4]
    at org.apache.commons.io.IOUtils.copy(IOUtils.java:1744) ~[commons-io-2.4.jar:2.4]
    at org.apache.commons.io.IOUtils.toByteArray(IOUtils.java:462) ~[commons-io-2.4.jar:2.4]

Here is the code I use:

InputStream in = DataService.class.getResourceAsStream("img.png");

        final HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.IMAGE_PNG);

        result.setData(new ResponseEntity<byte[]>(IOUtils.toByteArray(in), headers, HttpStatus.CREATED));

Comments on this question being marked for closure:

The question is related to programming as the API getResourceAsStream says this:

Returns A URL object or null if no resource with this name is found

My code was returning null even when I tried adding img.png to different locations.

This question is not a duplicate of this: getResourceAsStream() is always returning null

The answer in that question says that the file must be in the same directory as this but in this question, even though I added the image to the same location where class DataService was, it did not work.

Does it *actually* *`return`* a `NullPointerException`, or do you just mean it returns `null`? — Andy Turner, Mar 31 '16 at 16:29
Put it in the same directory as `DataService.java` and use `getResourceAsStream("img.png")` — erickson, Mar 31 '16 at 16:33
Build the project and look into build or target folder to check foe existence of img.png file. If its a maven project then put the image in src/resources folder. — Braj, Mar 31 '16 at 16:49
I have copied the file myself and also built it several times but still does not work — fscore, Mar 31 '16 at 16:50

fscore · Accepted Answer · 2016-03-31T18:19:12.060

1

When the project setup is done using Maven, adding the image to resources folder worked. Nothing from the code changed:

DataService.class.getClassLoader().getResource("img.png")

edited Mar 31 '16 at 18:19

answered Mar 31 '16 at 18:12

fscore

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score 1 · Answer 2 · answered Mar 31 '16 at 18:17

The issue here is that /src is probably the root of classpath (it depends on how you compile the project), and so you should put the img.png to src folder and the following code would work

DataService.class.getResourceAsStream("img.png");

Generally the getResourceAsStream() looks for the files from the root of classpath.

score 0 · Answer 3 · answered Mar 31 '16 at 16:34

0

you just need to do a small change, it's getResourceAsStream("/img.png") not getResourceAsStream("img.png").

I hope this will help.

answered Mar 31 '16 at 16:34

Dimitrios Begnis

823
6
16

Did not work with that change – fscore Mar 31 '16 at 16:41
Are you sure than, that the NPE is because of image path ? Because the following works perfectly fine for me: `BufferedImage img = ImageIO.read(DataService.class.getResourceAsStream("/img.jpg")); if (img != null) { System.out.println(" not null"); }` – Dimitrios Begnis Mar 31 '16 at 16:51

getResourceAsStream returns NullpointerException

3 Answers3