From d94565862a39e72316d5a0338c2a756b8563fb9f Mon Sep 17 00:00:00 2001
From: Sandro La Bruzzo <sandro.labruzzo@isti.cnr.it>
Date: Wed, 21 Jul 2021 21:23:11 +0200
Subject: [PATCH] fixed NPE

---
 .../src/main/java/eu/dnetlib/dhp/oa/merge/AuthorMerger.java      | 1 +
 1 file changed, 1 insertion(+)

diff --git a/dhp-common/src/main/java/eu/dnetlib/dhp/oa/merge/AuthorMerger.java b/dhp-common/src/main/java/eu/dnetlib/dhp/oa/merge/AuthorMerger.java
index fe9f94960..f900a276d 100644
--- a/dhp-common/src/main/java/eu/dnetlib/dhp/oa/merge/AuthorMerger.java
+++ b/dhp-common/src/main/java/eu/dnetlib/dhp/oa/merge/AuthorMerger.java
@@ -67,6 +67,7 @@ public class AuthorMerger {
 				a -> a
 					.getPid()
 					.stream()
+					.filter(Objects::nonNull)
 					.map(p -> new Tuple2<>(pidToComparableString(p), a)))
 			.collect(Collectors.toMap(Tuple2::_1, Tuple2::_2, (x1, x2) -> x1));