[
https://issues.apache.org/jira/browse/NETBEANS-407?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16374243#comment-16374243
]
Tobias Oelgarte commented on NETBEANS-407:
------------------------------------------
Your code doesn't actually check if _k_ might be _null_ or not. If _getFoo()_
would return _null_, then you would dereference _null_, because the line with
"_k instanceof Integer_" does nothing to prevent it from happening. If you add
the _if_ and the warning goes away, then everything should be fine, since
_instanceof_ also implies _!= null_. If it would still happen, then it is a bug.
> "Dereferencing possible null pointer" after doing instanceof on variable
> (false positive)
> -----------------------------------------------------------------------------------------
>
> Key: NETBEANS-407
> URL: https://issues.apache.org/jira/browse/NETBEANS-407
> Project: NetBeans
> Issue Type: Bug
> Components: java - FindBugs, java - Hints
> Affects Versions: 8.2, 9.0
> Reporter: Eirik Bakke
> Priority: Minor
>
> In the following example, the "boolean foo = k instanceof Integer" assignment
> causes a spurious "Dereferencing possible null pointer" warning to occur on
> the "k.doubleValue()" expression. I believe this did not happen in earlier
> NetBeans versions (pre-8.2). Note that if the assignment to "boolean foo" is
> replaced by an if statement ("if (k instanceof Integer)"), the warning goes
> away.
> {code:java}
> public class TestClass {
> private Number getFoo() {
> return 3;
> }
> public void testFoo() {
> Number k = getFoo();
> // The warning only occurs if this assignment is present.
> boolean foo = k instanceof Integer;
> // Warning on .doubleValue() here: "Dereferencing possible null pointer"
> System.out.println(k.doubleValue());
> }
> }
> {code}
> This bug was previously described at
> https://netbeans.org/bugzilla/show_bug.cgi?id=269324 .
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
For further information about the NetBeans mailing lists, visit:
https://cwiki.apache.org/confluence/display/NETBEANS/Mailing+lists
