From 78050c59abdb09cbdd8b4d0ce94e91514a6d6e5f Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Fri, 14 May 2021 15:19:04 +0200
Subject: [PATCH] Don't create a new ParserImpl on each parser() call (#11255)

Motivation:

ParserImpl is stateless and so we can use the same instance multiple times

Modifications:

- Make constructor private
- Return the same instance all the time

Result:

Less object creation
---
 .../java/io/netty/resolver/HostsFileEntriesProvider.java  | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/resolver/src/main/java/io/netty/resolver/HostsFileEntriesProvider.java b/resolver/src/main/java/io/netty/resolver/HostsFileEntriesProvider.java
index 8f0edb1fc6..aaf29208e0 100644
--- a/resolver/src/main/java/io/netty/resolver/HostsFileEntriesProvider.java
+++ b/resolver/src/main/java/io/netty/resolver/HostsFileEntriesProvider.java
@@ -120,7 +120,7 @@ public final class HostsFileEntriesProvider {
      * @return a new {@link HostsFileEntriesProvider.Parser}
      */
     public static Parser parser() {
-        return new ParserImpl();
+        return ParserImpl.INSTANCE;
     }
 
     static final HostsFileEntriesProvider EMPTY =
@@ -164,6 +164,12 @@ public final class HostsFileEntriesProvider {
 
         private static final InternalLogger logger = InternalLoggerFactory.getInstance(Parser.class);
 
+        static final ParserImpl INSTANCE = new ParserImpl();
+
+        private ParserImpl() {
+            // singleton
+        }
+
         @Override
         public HostsFileEntriesProvider parse() throws IOException {
             return parse(locateHostsFile(), Charset.defaultCharset());