SonarQube unable to understand Java inline expression for null check

Question

We are doing static code analysis using SonarQube. We are facing following Bug found by SonarQube

NullPointerException might be thrown as 'evt' is nullable here

in following code

try {
//business logic

}(Exception e){
    throw new MyException("Found issue for event " + evt.getDeatil());
}

So to remove this bug we have introduced small inline code for null check

try {
//business logic

 }(Exception e){
     throw new MyException("Found issue for event " + evt != null ?
       evt.getDeatil() : null);
}

Still SonarQube showing same violation bug after code change.

Could anyone please help us to find what we are missing here?

Answer 1

You have an error in line:

throw new MyException("Found issue for event " + evt != null ? evt.getDeatil() : null);

The problem is operators precedence . + is evaluated before ?: so your code is equal to:

String message = "Found issue for event " + evt;
throw new MyException(message != null ? evt.getDeatil() : null);

NullPointerException still can occur. Additional you've introduced a new problem - expression:

message != null

always evaluates to true .

To fix it you have to add curly brackets:

throw new MyException("Found issue for event " + (evt != null ? evt.getDeatil() : null));