diff --git a/poi-ooxml/src/main/java/org/apache/poi/xddf/usermodel/chart/XDDFChartData.java b/poi-ooxml/src/main/java/org/apache/poi/xddf/usermodel/chart/XDDFChartData.java
index c8e92fea643..b75394c0036 100644
--- a/poi-ooxml/src/main/java/org/apache/poi/xddf/usermodel/chart/XDDFChartData.java
+++ b/poi-ooxml/src/main/java/org/apache/poi/xddf/usermodel/chart/XDDFChartData.java
@@ -170,8 +170,7 @@ public void replaceData(XDDFDataSource<?> category, XDDFNumericalDataSource<? ex
             if (categoryData != null && values != null) {
                 int numOfPoints = category.getPointCount();
                 if (numOfPoints != values.getPointCount()) {
-                    LOGGER.warn("Category and values must have the same point count, but had " +
-                            numOfPoints + " categories and " + values.getPointCount() + " values.");
+                    LOGGER.warn("Category and values must have the same point count, but had {} categories and {} values.", numOfPoints, values.getPointCount());
                 }
             }
             this.categoryData = category;