Added missing default constructor to EuclideanDistance class (#818)

* Added missing default constructor

* Update CHANGELOG.md

Author: cicirello

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased] - 2025-05-16
+## [Unreleased] - 2025-10-04
 
 ### Added
 
@@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Removed
 
 ### Fixed
+* Added missing default constructor to `org.cicirello.search.problems.tsp.EuclideanDistance` to avoid undocumented constructor.
 
 ### Dependencies
 

src/main/java/org/cicirello/search/problems/tsp/EuclideanDistance.java

@@ -1,6 +1,6 @@
 /*
  * Chips-n-Salsa: A library of parallel self-adaptive local search algorithms.
- * Copyright (C) 2002-2022 Vincent A. Cicirello
+ * Copyright (C) 2002-2025 Vincent A. Cicirello
  *
  * This file is part of Chips-n-Salsa (https://chips-n-salsa.cicirello.org/).
  *
@@ -28,6 +28,14 @@
  */
 public final class EuclideanDistance implements TSPEdgeDistance {
 
+  /** Constructs the Euclidean distance function. */
+  public EuclideanDistance() {
+    // Deliberately empty: no initialization necessary.
+    // Added empty default constructor for javadoc purposes, such as
+    // preventing warning during compilation, and to ensure the documentation
+    // is not blank.
+  }
+
   @Override
   public double distance(double x1, double y1, double x2, double y2) {
     double deltaX = x1 - x2;