User ternary expression

Author: garydgregory

src/main/java/org/apache/commons/csv/CSVParser.java

@@ -524,12 +524,8 @@ private Headers createHeaders() throws IOException {
                 }
             }
         }
-        if (headerNames == null) {
-            headerNames = Collections.emptyList(); // immutable
-        } else {
-            headerNames = Collections.unmodifiableList(headerNames);
-        }
-        return new Headers(hdrMap, headerNames);
+        // Make header names Collection immutable
+        return new Headers(hdrMap, headerNames == null ? Collections.emptyList() : Collections.unmodifiableList(headerNames));
     }
 
     /**