diff --git a/jsprit-core/pom.xml b/jsprit-core/pom.xml
index f3d79fc0..3ae778a0 100644
--- a/jsprit-core/pom.xml
+++ b/jsprit-core/pom.xml
@@ -42,6 +42,12 @@
             <version>${logger.version}</version>
         </dependency>
 
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+            <version>21.0</version>
+        </dependency>
+
     </dependencies>