singleton pattern created

src/patterns/singleton/MySingleton.java

@@ -0,0 +1,31 @@
+package patterns.singleton;
+
+/**
+ * Created by Bruno on 31.01.2018.
+ * singleton pattern can for example be used for database connections
+ *
+ */
+public class MySingleton {
+
+
+    private static MySingleton instance = null;
+
+    //make singleton protected so you can only start an instance from the getInstance method
+    protected MySingleton(){};
+
+    public static MySingleton getInstance(){
+        //create only an instance if there is none
+        if (instance == null){
+            //overwrite instance with a new instance
+            instance = new MySingleton();
+            System.out.println("Singleton instance created");
+            return instance;
+        }
+        else {
+            //when there is already an instance, you just return the existing one
+            System.out.println("there is already an instance. Here it is");
+            return instance;
+        }
+    }
+
+}

src/patterns/singleton/SingletonTester.java

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+package patterns.singleton;
+
+/**
+ * Created by Bruno on 31.01.2018.
+ */
+public class SingletonTester {
+
+    public static void main(String[] args) {
+        //sout should say that there is it has created a new instance
+        MySingleton.getInstance();
+
+        //sout should return the existing instance
+        MySingleton.getInstance();
+    }
+}