diff --git a/matsim/src/main/java/org/matsim/utils/objectattributes/attributeconverters/StringConverter.java b/matsim/src/main/java/org/matsim/utils/objectattributes/attributeconverters/StringConverter.java
index 3a600e82bc1..bf9a209818a 100644
--- a/matsim/src/main/java/org/matsim/utils/objectattributes/attributeconverters/StringConverter.java
+++ b/matsim/src/main/java/org/matsim/utils/objectattributes/attributeconverters/StringConverter.java
@@ -31,14 +31,10 @@
  */
 public class StringConverter implements AttributeConverter<String> {
 	private final Map<String, String> stringCache = new ConcurrentHashMap<>(1000);
+
 	@Override
 	public String convert(String value) {
-		String s = this.stringCache.get(value);
-		if (s == null) {
-			s = value;
-			this.stringCache.put(s, s);
-		}
-		return s;
+		return stringCache.computeIfAbsent(value, k -> k);
 	}
 
 	@Override