[NETBEANS-5667] False positive: Dereferencing possible Null Pointer Exception

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 12.3
• Labels: false npe nullpointerexception warn warning
• Assignee: Unassigned
• Reporter: Nakarukatoshi
• Created: 07/May/21 10:51
• Updated: 07/May/21 10:53

Description

As posted on NETBEANS-1480, here is another clear example of the fake NullPointerException:

 

public static void foo(Object bar) {
    Objects.requireNonNull(bar, "[bar] must not be null.");
    if (bar instanceof String) {
        System.out.println(bar.toString());
    } else {
        throw new IllegalArgumentException("[" + bar.getClass().getSimpleName() + "] not supported.");
        }
}

In other words, after the Objects#requireNonNull(Object, String) check, if I do an if-else with an instanceof operator, the "else" section will warn about a NullPointerException (the red method)