diff --git a/java/boxing/IntegerBoxing.java b/java/boxing/IntegerBoxing.java
new file mode 100644
index 0000000..b619e21
--- /dev/null
+++ b/java/boxing/IntegerBoxing.java
@@ -0,0 +1,4 @@
+// エラーが出ないからOKという考え方をやめ、型をしっかり考えた方が良い
+
+        final int sysCdCount = Integer.parseInt(m.get("UNIQUE_SYSTEM_CD_COUNT").toString());
+        final int dcfCdCount = Integer.parseInt(m.get("UNIQUE_DCF_DR_CD_COUNT").toString());