NullPointerException in Print Method

Question

I have a method in a Restful WebService, which prints all the information of a given record, based on its id.

When I test this method, I am getting a NullPointerException.

@SuppressWarnings("null")
@RequestMapping("print")
@ResponseBody
public ResponseEntity<Map<String, Object>> print(@RequestParam("id") Long id) {
    Map<String, Object> mapPrint=null;
    ResourceManage resourceManage = resourceManageService.findByIdwithowner(id);
    Map<String, Object> params = new HashMap<String, Object>();
    if (resourceManage.getDocumentOwner() != null && resourceManage.getDocumentOwner().getId() != null)
        params.put("documentOwner", resourceManage.getDocumentOwner().getId());
    else
        params.put("documentOwner", null);
    params.put("resId", id);
    mapPrint.put("format", "pdf");
    mapPrint.put("reportQuery", resourceManageService.generateReportQuery(params));
    return new ResponseEntity<Map<String, Object>>(mapPrint, HttpStatus.OK);
}

You should also provide an example call of this method which causes the NPE. — Florian Albrecht, Nov 17 '16 at 12:25
Possible duplicate of [What is a NullPointerException, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix-it) — Jens, Nov 17 '16 at 12:26
@Christian I am getting the NPE on mapPrint.put("format", "pdf"); — N V, Nov 17 '16 at 12:40

score 3 · Accepted Answer · edited Nov 17 '16 at 12:46

3

You're getting an NPE, because you haven't instantiated mapPrint. Change

Map<String, Object> mapPrint=null;

to

Map<String, Object> mapPrint = new HashMap<>();

edited Nov 17 '16 at 12:46

answered Nov 17 '16 at 12:44

Shem

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NullPointerException in Print Method

1 Answers1