diff --git a/s-day07/src/com/inmind/functional_interface02/Demo04.java b/s-day07/src/com/inmind/functional_interface02/Demo04.java
index 6a201e4..bf469f5 100644
--- a/s-day07/src/com/inmind/functional_interface02/Demo04.java
+++ b/s-day07/src/com/inmind/functional_interface02/Demo04.java
@@ -10,6 +10,71 @@ package com.inmind.functional_interface02;
 扩展:为何在一个接口中某些抽象方法不需要被重写??
 在一个类中如果单继承和多实现,单继承的方法优先级高于接口中的方法定义,导致父类方法中
 如果有跟接口中重名的方法实现的话,那么就相当于在子类中默认重写了接口的方法
+-----------------------------------------------
+函数式接口的使用:
+函数式接口可以作为
+        参数类型
+        返回值类型
+        变量类型
+
+其实就是将lambda表达式作为函数式接口的实现类对象
+
  */
 public class Demo04 {
+    //函数式接口作为返回值类型
+    public static void main(String[] args) {
+        //获取一个函数式接口对象
+        MyFunctionalInterface impl = getInterface();
+        int value = getValue(impl, 10, 2);
+        System.out.println(value);
+    }
+
+
+
+    public static MyFunctionalInterface getInterface(){
+        //变量类型
+        /*MyFunctionalInterface impl = new MyFunctionalInterface() {
+            @Override
+            public int getValue(int a, int b) {
+                return a-b;
+            }
+        };*/
+
+        //变量类型
+        /*MyFunctionalInterface impl = (int a, int b)->{
+            return a-b;
+        };*/
+
+//        MyFunctionalInterface impl = ( a,  b)-> a-b;
+
+
+        return ( a,  b)-> a-b;
+    }
+
+
+
+
+
+
+
+    //---------------------------------------------------------------------------------
+    //函数式接口作为参数类型
+    public static void method1(String[] args) {
+        /*int result = getValue(new MyIFunctionalnterface() {
+            @Override
+            public int getValue(int a, int b) {
+                return a+b;
+            }
+        },10,2);*/
+//        int result = getValue((a, b) -> a + b, 10, 2);
+        int result = getValue((int a, int b) -> {return a + b;}, 10, 2);
+
+        System.out.println(result);
+    }
+
+    //接口回调：将我们的业务逻辑嵌入到源码方法中
+    public static int getValue(MyFunctionalInterface impl, int x, int y){
+        int result = impl.getValue(x, y);
+        return result;
+    }
 }
diff --git a/s-day07/src/com/inmind/functional_interface02/Demo05.java b/s-day07/src/com/inmind/functional_interface02/Demo05.java
new file mode 100644
index 0000000..a50283c
--- /dev/null
+++ b/s-day07/src/com/inmind/functional_interface02/Demo05.java
@@ -0,0 +1,4 @@
+package com.inmind.functional_interface02;
+
+public class Demo05 {
+}
diff --git a/s-day07/src/com/inmind/functional_interface02/MyIFunctionalnterface.java b/s-day07/src/com/inmind/functional_interface02/MyFunctionalInterface.java
similarity index 56%
rename from s-day07/src/com/inmind/functional_interface02/MyIFunctionalnterface.java
rename to s-day07/src/com/inmind/functional_interface02/MyFunctionalInterface.java
index efef907..696dd8c 100644
--- a/s-day07/src/com/inmind/functional_interface02/MyIFunctionalnterface.java
+++ b/s-day07/src/com/inmind/functional_interface02/MyFunctionalInterface.java
@@ -1,13 +1,13 @@
 package com.inmind.functional_interface02;
 
 @FunctionalInterface
-public interface MyIFunctionalnterface {
+public interface MyFunctionalInterface {
 //    void method();
 //    void method(int a);
 //    int method(int a);
-    int method();
+    int getValue(int a,int b);
 
-    boolean equals(Object obj);
+    /*boolean equals(Object obj);
     String toString();
-    int hashCode();
+    int hashCode();*/
 }