From c141ef400975be45469a0f7e4fcb2d9c5d9e6a1b Mon Sep 17 00:00:00 2001
From: Kui LIU <brucekuiliu@gmail.com>
Date: Wed, 11 Oct 2017 15:01:48 +0200
Subject: [PATCH] Fix the problem of using '+=' operator to concatenate strings
 a in a loop.

The method is building a String using concatenation in a loop.
In each iteration, the String is converted to a StringBuilder, appended to, and converted back to a String.
This can lead to a cost quadratic in the number of iterations, as the growing string is recopied in each iteration.
Better performance can be obtained by using a StringBuilder explicitly.
http://findbugs.sourceforge.net/bugDescriptions.html#SBSC_USE_STRINGBUFFER_CONCATENATION
---
 src/main/org/apache/tools/ant/Main.java | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/main/org/apache/tools/ant/Main.java b/src/main/org/apache/tools/ant/Main.java
index b104fd33a..a7d477671 100644
--- a/src/main/org/apache/tools/ant/Main.java
+++ b/src/main/org/apache/tools/ant/Main.java
@@ -1292,9 +1292,9 @@ public class Main implements AntMain {
         // now, start printing the targets and their descriptions
         final String lSep = System.getProperty("line.separator");
         // got a bit annoyed that I couldn't find a pad function
-        String spaces = "    ";
+        StringBuilder spaces = new StringBuilder("    ");
         while (spaces.length() <= maxlen) {
-            spaces += spaces;
+            spaces.append(spaces);
         }
         final StringBuilder msg = new StringBuilder();
         msg.append(heading).append(lSep).append(lSep);