diff --git a/docs/java/basis/why-there-only-value-passing-in-java.md b/docs/java/basis/why-there-only-value-passing-in-java.md
index fabe3abb..9167002e 100644
--- a/docs/java/basis/why-there-only-value-passing-in-java.md
+++ b/docs/java/basis/why-there-only-value-passing-in-java.md
@@ -26,7 +26,7 @@ String hello = "Hello!";
 sayHello(hello);
 // str 为形参
 void sayHello(String str) {
-			System.out.println(str);
+    System.out.println(str);
 }
 ```