From 76c6fabd6734af68e5657b16c50af98ee4f8ffda Mon Sep 17 00:00:00 2001
From: Markus Rathgeb <maggu2810@gmail.com>
Date: Thu, 16 Oct 2014 21:51:49 +0200
Subject: [PATCH] use initialization-on-demand holder idiom

This gives us a highly efficient thread-safe "singleton" cache, without
synchronization overhead...

lecture:
https://en.wikipedia.org/wiki/Initialization-on-demand_holder_idiom
---
 src/main/java/jssc/SerialNativeAccess.java | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/main/java/jssc/SerialNativeAccess.java b/src/main/java/jssc/SerialNativeAccess.java
index f8c163695..ed0afd97d 100644
--- a/src/main/java/jssc/SerialNativeAccess.java
+++ b/src/main/java/jssc/SerialNativeAccess.java
@@ -38,16 +38,16 @@
 public class SerialNativeAccess {
     private int osType = -1;
     private static SerialNativeInterface sni = new SerialNativeInterface();
-    private static SerialNativeAccess instance = null;
+
+    private static class LazyHolder {
+        private static final SerialNativeAccess INSTANCE = new SerialNativeAccess();
+    }
     
     public static SerialNativeAccess getInstance() {
-        if (SerialNativeAccess.instance == null) {
-            SerialNativeAccess.instance = new SerialNativeAccess();
-        } 
-        return SerialNativeAccess.instance;
+        return LazyHolder.INSTANCE;
     }
     
-    public SerialNativeAccess() {
+    private SerialNativeAccess() {
         String libFolderPath;
         String libName;