如何抑制字段或局部变量的FindBugs警告

Question

I would like to suppress FindBugs warnings for specific fields or local variables. FindBugs documents that the Target can be Type, Field, Method, Parameter, Constructor, Package for its edu.umd.cs.findbugs.annotations.SuppressWarning annotation [1]. But it does not work for me to annotate the field, only when I annotate the method the warning gets suppressed.

Annotating a whole method seems to broad to me. Is there any way to suppress warnings on specific fields? There is another related question [2], but no answer.

[1] http://findbugs.sourceforge.net/manual/annotations.html

[2] Suppress FindBugs warnings in Eclipse

Demo code:

public class SyncOnBoxed
{
    static int counter = 0;
    // The following SuppressWarnings does NOT prevent the FindBugs warning
    @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="DL_SYNCHRONIZATION_ON_BOXED_PRIMITIVE")
    final static Long expiringLock = new Long(System.currentTimeMillis() + 10);

    public static void main(String[] args) {
        while (increment(expiringLock)) {
            System.out.println(counter);
        }
    }

    // The following SuppressWarnings prevents the FindBugs warning
    @edu.umd.cs.findbugs.annotations.SuppressWarnings(value="DL_SYNCHRONIZATION_ON_BOXED_PRIMITIVE")
    protected static boolean increment(Long expiringLock)
    {
        synchronized (expiringLock) { // <<< FindBugs warning is here: Synchronization on Long in SyncOnBoxed.increment()
            counter++;
        }
        return expiringLock > System.currentTimeMillis(); // return false when lock is expired
    }
}

Answer 1

@SuppressFBWarnings on a field only suppresses findbugs warnings reported for that field declaration, not every warning associated with that field.

For example, this suppresses the "Field only ever set to null" warning:

@SuppressFBWarnings("UWF_NULL_FIELD")
String s = null;

I think the best you can do is isolate the code with the warning into the smallest method you can, then suppress the warning on the whole method.

Note: @SuppressWarnings was marked deprecated in favor of @SuppressFBWarnings

Answer 2

Check http://findbugs.sourceforge.net/manual/filter.html#d0e2318 There is a Local tag that can be used with the Method tag. Here you can specify which bug should be excluded for a specific local variable. Example:

<FindBugsFilter>
  <Match>
        <Class name="<fully-qualified-class-name>" />
        <Method name="<method-name>" />
        <Local name="<local-variable-name-in-above-method>" />
        <Bug pattern="DLS_DEAD_LOCAL_STORE" />
  </Match>
</FindBugsFilter>