add @Override annotations

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1747825 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/ss/formula/udf/AggregatingUDFFinder.java

@@ -44,6 +44,7 @@ public class AggregatingUDFFinder implements UDFFinder {
      * @param name Name of function.
      * @return Function executor. <code>null</code> if not found
      */
+    @Override
     public FreeRefFunction findFunction(String name) {
         FreeRefFunction evaluatorForFunction;
         for (UDFFinder pack : _usedToolPacks) {

src/java/org/apache/poi/ss/formula/udf/DefaultUDFFinder.java

@@ -44,6 +44,7 @@ public final class DefaultUDFFinder implements UDFFinder {
         _functionsByName = m;
     }
 
+    @Override
     public FreeRefFunction findFunction(String name) {
         return _functionsByName.get(name.toUpperCase(Locale.ROOT));
     }

src/java/org/apache/poi/ss/formula/udf/IndexedUDFFinder.java

@@ -35,6 +35,7 @@ public class IndexedUDFFinder extends AggregatingUDFFinder {
         _funcMap = new HashMap<Integer, String>();
     }
 
+    @Override
     public FreeRefFunction findFunction(String name) {
         FreeRefFunction func = super.findFunction(name);
         if (func != null) {

src/java/org/apache/poi/ss/formula/udf/UDFFinder.java

@@ -26,6 +26,7 @@ import org.apache.poi.ss.formula.functions.FreeRefFunction;
  * @author PUdalau
  */
 public interface UDFFinder {
+    // FIXME: Findbugs error: IC_SUPERCLASS_USES_SUBCLASS_DURING_INITIALIZATION
     public static final UDFFinder DEFAULT = new AggregatingUDFFinder(AnalysisToolPak.instance);
 
     /**