diff --git a/JavaOOP/src/Java25.java b/JavaOOP/src/Java25.java
new file mode 100644
index 00000000..84f6b686
--- /dev/null
+++ b/JavaOOP/src/Java25.java
@@ -0,0 +1,16 @@
+import poly.Radio;
+import poly.RemoCon;
+import poly.TV;
+
+public class Java25 {
+    public static void main(String[] args) {
+        RemoCon r = new TV();
+        for (int i = 0; i < 10; i++) {
+            r.chUp();
+        }
+        for (int i = 0; i < 10; i++) {
+            r.chDown();
+        }
+        r.internet();
+    }
+}
diff --git a/JavaOOP/src/Java26.java b/JavaOOP/src/Java26.java
new file mode 100644
index 00000000..aa4760f5
--- /dev/null
+++ b/JavaOOP/src/Java26.java
@@ -0,0 +1,15 @@
+import myObject.DBConnect;
+import myObject.JavaMySQLDriver;
+import myObject.JavaOracleDriver;
+
+public class Java26 {
+    public static void main(String[] args) {
+
+        // Oracle, MySQL 등을 사용하기 위해 Driver class 가 필요
+        DBConnect conn = new JavaOracleDriver();
+        conn.getConnection("url", "id", "password");
+
+        conn = new JavaMySQLDriver();
+        conn.getConnection("url", "id", "password");
+    }
+}
diff --git a/JavaOOP/src/myObject/DBConnect.java b/JavaOOP/src/myObject/DBConnect.java
new file mode 100644
index 00000000..3465004b
--- /dev/null
+++ b/JavaOOP/src/myObject/DBConnect.java
@@ -0,0 +1,6 @@
+package myObject;
+
+public interface DBConnect {
+    // 규약
+    void getConnection(String url, String user, String password);
+}
diff --git a/JavaOOP/src/myObject/JavaMySQLDriver.java b/JavaOOP/src/myObject/JavaMySQLDriver.java
new file mode 100644
index 00000000..beb723a9
--- /dev/null
+++ b/JavaOOP/src/myObject/JavaMySQLDriver.java
@@ -0,0 +1,8 @@
+package myObject;
+
+public class JavaMySQLDriver implements DBConnect{
+    @Override
+    public void getConnection(String url, String user, String password) {
+        System.out.println("MySQL DB에 접속합니다.");
+    }
+}
diff --git a/JavaOOP/src/myObject/JavaOracleDriver.java b/JavaOOP/src/myObject/JavaOracleDriver.java
new file mode 100644
index 00000000..fded2638
--- /dev/null
+++ b/JavaOOP/src/myObject/JavaOracleDriver.java
@@ -0,0 +1,8 @@
+package myObject;
+
+public class JavaOracleDriver implements DBConnect{
+    @Override
+    public void getConnection(String url, String user, String password) {
+        System.out.println("Oracle DB에 접속합니다.");
+    }
+}
diff --git a/JavaOOP/src/poly/TV.java b/JavaOOP/src/poly/TV.java
index a574368b..48774e70 100644
--- a/JavaOOP/src/poly/TV.java
+++ b/JavaOOP/src/poly/TV.java
@@ -1,14 +1,25 @@
 package poly;
 
 public class TV implements RemoCon{
+    int currCH = 95;
     @Override
     public void chUp() {
-        System.out.println("TV의 채널이 올라간다.");
+        if (currCH < RemoCon.MAXCH) {
+            currCH++;
+        } else {
+            currCH = 1;
+        }
+        System.out.println("TV의 채널이 올라간다. : " + currCH);
     }
 
     @Override
     public void chDown() {
-        System.out.println("TV의 채널이 내려간다.");
+        if (currCH > RemoCon.MINCH) {
+            currCH--;
+        } else {
+            currCH = RemoCon.MAXCH;
+        }
+        System.out.println("TV의 채널이 내려간다. : " + currCH);
     }
 
     @Override