From e6086efc53804cf3e29d29fd6b2f1b8f958f9130 Mon Sep 17 00:00:00 2001
From: Claudio Atzori <claudio.atzori@isti.cnr.it>
Date: Sun, 3 Dec 2023 13:33:20 +0100
Subject: [PATCH] avoid NPEs in Vocabulary.getTermBySynonym

---
 .../java/eu/dnetlib/dhp/common/vocabulary/Vocabulary.java    | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/dhp-common/src/main/java/eu/dnetlib/dhp/common/vocabulary/Vocabulary.java b/dhp-common/src/main/java/eu/dnetlib/dhp/common/vocabulary/Vocabulary.java
index 2ab23bda6..94e7f5221 100644
--- a/dhp-common/src/main/java/eu/dnetlib/dhp/common/vocabulary/Vocabulary.java
+++ b/dhp-common/src/main/java/eu/dnetlib/dhp/common/vocabulary/Vocabulary.java
@@ -63,7 +63,10 @@ public class Vocabulary implements Serializable {
 	}
 
 	public VocabularyTerm getTermBySynonym(final String syn) {
-		return getTerm(synonyms.get(syn.toLowerCase()));
+		return Optional
+			.ofNullable(syn)
+			.map(s -> getTerm(synonyms.get(s.toLowerCase())))
+			.orElse(null);
 	}
 
 	public Qualifier getTermAsQualifier(final String termId) {