From bd9ca6e169ebb2bfa1848f3ca94291a7c0beddc5 Mon Sep 17 00:00:00 2001
From: Minecrell <minecrell@minecrell.net>
Date: Mon, 18 Sep 2017 12:00:03 +0200
Subject: [PATCH] Use Log4j IOStreams to redirect System.out/err to logger

Log4j2 provides an optimized implementation of PrintStream that
redirects its output to a logger. Use it instead of a custom
implementation for minor performance improvements and some fixes.

With the old implementation, each call to System.print()
results in a separate line, even though it should not result in
a line break. Log4j's implementation handles it correctly.

diff --git a/pom.xml b/pom.xml
index d93a180de9..815f9ef393 100644
--- a/pom.xml
+++ b/pom.xml
@@ -62,6 +62,11 @@
             <version>2.8.1</version>
             <scope>runtime</scope>
         </dependency>
+        <dependency>
+            <groupId>org.apache.logging.log4j</groupId>
+            <artifactId>log4j-iostreams</artifactId>
+            <version>2.8.1</version>
+        </dependency>
         <dependency>
             <groupId>org.ow2.asm</groupId>
             <artifactId>asm</artifactId>
diff --git a/src/main/java/net/minecraft/server/DedicatedServer.java b/src/main/java/net/minecraft/server/DedicatedServer.java
index 9fdb6d100b..674609cad3 100644
--- a/src/main/java/net/minecraft/server/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/DedicatedServer.java
@@ -131,8 +131,10 @@ public class DedicatedServer extends MinecraftServer implements IMinecraftServer
         */
         // Paper end
 
-        System.setOut(new PrintStream(new LoggerOutputStream(logger, Level.INFO), true));
-        System.setErr(new PrintStream(new LoggerOutputStream(logger, Level.WARN), true));
+        // Paper start - Use Log4j IOStreams
+        System.setOut(org.apache.logging.log4j.io.IoBuilder.forLogger(logger).setLevel(Level.INFO).buildPrintStream());
+        System.setErr(org.apache.logging.log4j.io.IoBuilder.forLogger(logger).setLevel(Level.WARN).buildPrintStream());
+        // Paper end
         // CraftBukkit end
 
         thread.setDaemon(true);
-- 
2.19.0