From ffeeed9250ab26e420c6656a8a0e56649d26781b Mon Sep 17 00:00:00 2001
From: haerong22 <haerong22@naver.com>
Date: Mon, 15 Feb 2021 17:12:49 +0900
Subject: [PATCH] java8 : date/time api

---
 java8to11/src/dateTime/App.java | 39 +++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 java8to11/src/dateTime/App.java

diff --git a/java8to11/src/dateTime/App.java b/java8to11/src/dateTime/App.java
new file mode 100644
index 00000000..ca46a07a
--- /dev/null
+++ b/java8to11/src/dateTime/App.java
@@ -0,0 +1,39 @@
+package dateTime;
+
+import java.util.Calendar;
+import java.util.Date;
+import java.util.GregorianCalendar;
+
+public class App {
+
+    public static void main(String[] args) throws InterruptedException {
+
+        /**
+         * java 8 의 Date-Time API
+         * - Clear
+         * - Fluent
+         * - Immutable
+         * - Extensible
+         */
+        
+
+        // 기존의 Date, Time 관련 문제점
+        Date date = new Date();
+        long time = date.getTime(); // epoch time
+        System.out.println(date);
+        System.out.println(time);
+
+        // date 변경이 가능 ( mutable ) -> thread safe 하지 않다.
+        Thread.sleep(1000 * 3);
+        Date after3Seconds = new Date();
+        System.out.println(after3Seconds);
+        after3Seconds.setTime(time);
+        System.out.println(after3Seconds);
+
+        // month 가 0부터 시작 : 8월 이면 7, int 값을 받는다. -> type safe 하지 않다.
+        Calendar birthDay = new GregorianCalendar(2092, Calendar.AUGUST, 8);
+        System.out.println(birthDay.getTime());
+        birthDay.add(Calendar.DAY_OF_YEAR, 1);
+        System.out.println(birthDay.getTime());
+    }
+}