fix

docs/chapter05.md

@@ -266,15 +266,11 @@ System.out.println(append.convert("Hello", "Lambda")); // 输出 "Hello, Lambda"
 ```java
 // 假设我们有一个简单的类
 class Example {
-  private final int value;
-
-  public Example(int value) {
-    this.value = value;
+  public Example() {
   }
   
-  @Override
-  public String toString() {
-    return "Example{" + "value=" + value + '}';
+  public String doSomething() {
+    return "Example do something“;
   }
 }
 
@@ -286,13 +282,11 @@ interface ExampleSupplier {
 public class Main {
   public static void main(String[] args) {
     // 使用lambda表达式和构造函数引用创建ExampleSupplier实例
-    ExampleSupplier supplier = () -> new Example(42);
+    ExampleSupplier supplier = Example::new;
 
     // 使用ExampleSupplier实例来创建Example对象
     Example example = supplier.get();
-
-    // 输出结果
-    System.out.println(example);
+    example.doSomething();
   }
 }
 ```