comparing List<Integer> to Integer Object using Java Stream

I’m having issues with using streams in Java. Probably not the right way im doing. Can someone please point what’s going wrong.

I have a java class Users.java with List as follows:

/////..............

private List<Integer> userDocIdsToView = new ArrayList<Integer>();
 


@Transient
    public List<Integer> getUserDocIdsToView() {
        return userDocIdsToView;
    }

    public void setUserDocIdsToView(List<Integer> userDocIdsToView) {
        this.userDocIdsToView = userDocIdsToView;
    }
    
    ...////

Im trying to use this and compare this list with a Integer using stream as follows:

@RequestMapping(value = {"getDoc/{documentId}"}, method = RequestMethod.POST)
    public ResponseEntity<?> getDoc(HttpServletRequest req, @PathVariable(required = true) String documentId) {
        
        try {
            System.out.println("Inside getDoc "+documentId+" ->"+"List "+userObj.getUserDocIdsToView()+" - "+Stream.of(userObj.getUserDocIdsToView()).anyMatch(num -> Objects.equals(num,  Integer.valueOf(documentId))));
            
            if(documentId != null && userObj.getUserDocIdsToView().size() > 0 && Stream.of(userObj.getUserDocIdsToView()).anyMatch(num -> Objects.equals(num, Integer.valueOf(documentId)))) {
                System.out.println("Passed the condition");
            }
            }
}

The above code looks good but once I run , the sysout is as follows:

Inside getDoc 31 ->List [31, 48, 57, 59, 66, 67, 68, 73, 89, 102, 251] - false

I am converting String to Integer Object and comparing that with List. Where am i going wrong?

>Solution :

The problem is that you are using Stream.of(List). As a result you have a stream of one element and this element is the list. And of course, your list is not equal to the number.

userObj.getUserDocIdsToView().stream().anyMatch(num -> Objects.equals(num, Integer.valueOf(documentId))));

And don’t forget about potential NPEs, check that user object and docIdsToView are not null. Or use Optional