Databases
StackOverflow2013
Postsdbo
PO@Nullable input in Google Guava Function interface triggers FindBugs warning
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO@Nullable input in Google Guava Function interface triggers FindBugs warning
    primarykey
    data
    text
    <p>The <code>com.google.common.base.Function</code> interface (from <a href="http://code.google.com/p/guava-libraries/wiki/Release13">Google Guava</a>) defines <code>apply</code> as:</p> <p><code>@Nullable T apply(@Nullable F input);</code> </p> <p>The method has the following javadoc note:</p> <p><code>@throws NullPointerException if {@code input} is null and this function does not accept null arguments</code>.</p> <p>FindBugs complains about my implementation of Function:</p> <pre><code>private static final class Example implements Function&lt;MyBean, String&gt; { @Override @Nullable public String apply(@Nullable MyBean input) { if (null == input) { throw new NullPointerException(); } return input.field; } } </code></pre> <p>with a <strong>high-priority</strong> warning:</p> <blockquote> <p>NP_PARAMETER_MUST_BE_NONNULL_BUT_MARKED_AS_NULLABLE, Priority: High</p> <p>input must be nonnull but is marked as nullable</p> <p>This parameter is always used in a way that requires it to be nonnull, but the parameter is explicitly annotated as being Nullable. Either the use of the parameter or the annotation is wrong.</p> </blockquote> <p>My function does not support <code>null</code> inputs and an exception is thrown if that is the case. If I understand correctly, FindBugs treats this as a requirement for non-null.</p> <p>To me it looks like a contradiction: input is @Nullable but method @throws NullPointerException when it is null. Am I missing something? </p> <p>The only way to get rid of the warning that I can see is manual suppression. (Guava code is out of my control, obviously).</p> <p>Who is wrong about the usage of @Nullable annotation, FindBugs, Guava or myself?</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USvitaly
    1. USvitaly
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. PO@Nullable input in Google Guava Function interface triggers FindBugs warning
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO@Nullable input in Google Guava Function interface triggers FindBugs warning
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO@Nullable input in Google Guava Function interface triggers FindBugs warning
      1. This table or related slice is empty.
      1. VTUpMod
    1. COYou're saying you'll accept null in the signature, and then you're *rejecting* a null value in the body. It sounds like you've misunderstood the purpose of `@Nullable`.
      singulars
      1. PO@Nullable input in Google Guava Function interface triggers FindBugs warning
      1. USJon Skeet
    2. COThe only reason why I added `@Nullable` for input parameter is that it is what `Function` interface defines. Anyway, I removed `@Nullable` annotation from the parameter as @Xaerxess suggested but FindBugs keeps complaining.
      singulars
      1. PO@Nullable input in Google Guava Function interface triggers FindBugs warning
      1. USvitaly
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload