diff --git a/src/main/java/info/istlab/dp/dp1/SingletonTest.java b/src/main/java/info/istlab/dp/dp1/SingletonTest.java
new file mode 100644
index 0000000..0e4afb4
--- /dev/null
+++ b/src/main/java/info/istlab/dp/dp1/SingletonTest.java
@@ -0,0 +1,40 @@
+package info.istlab.dp.dp1;
+
+import java.util.Calendar;
+import java.util.Date;
+
+class Singleton {
+    private static Singleton onlyone;
+    public static Singleton getOnlyOne() {
+        if (onlyone == null)
+            onlyone = new Singleton();
+        return onlyone;
+    }
+    Date created;
+    private Singleton() {
+        created = Calendar.getInstance().getTime();
+    }
+    public String toString() {
+        return hashCode()+" "+created.toString();
+    }
+}
+
+public class SingletonTest {
+    public static void main(String[] args) {
+        // Singleton single = new Singleton();
+        Singleton single1 = Singleton.getOnlyOne();
+        System.out.println(single1.toString());
+        SingletonTest.wait(5);
+        Singleton single2 = Singleton.getOnlyOne();
+        System.out.println(single2.toString());
+    }
+
+    public static void wait(int sec) {
+        try {
+            Thread.sleep(sec * 1000);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+}
+