Incorrect FindBugs analysis with CheckForNull annotation on field.

gistfile1.java

import javax.annotation.CheckForNull;
import javax.annotation.Nullable;


public class WrongNPWarning {
  @CheckForNull
  private String foo;

  public WrongNPWarning() {
    Runnable r = new Runnable() {
      @Override
      public void run() {
        if (foo != null) {
          /*
           * Getting a findbugs warning on next line:
           * "Possible null pointer dereference in WrongNPWarning$1.run() due to return value of called method"
           */
          System.out.println(foo.equals("foo"));
        }
      }
    };
  }

  public void doFoo() {
    if (foo != null) {
      // No warning here.
      System.out.println(foo.equals("foo"));
    }
    Runnable r = new Runnable() {
      @Override
      public void run() {
        if (foo != null) {
          /*
           * Getting a findbugs warning on next line:
           * "Possible null pointer dereference in WrongNPWarning$1.run() due to return value of called method"
           */
          System.out.println(foo.equals("foo"));
        }
      }
    };
  }
}