From 6debe066f1552ec36d715fa34a0f567c1f0e9152 Mon Sep 17 00:00:00 2001
From: Marc Zwart <marc@tamtam.nl>
Date: Tue, 20 Mar 2018 16:01:48 +0100
Subject: [PATCH] remove dangerous instance of double-checked locking

---
 .../java/mage/client/util/gui/ArrowBuilder.java    | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/Mage.Client/src/main/java/mage/client/util/gui/ArrowBuilder.java b/Mage.Client/src/main/java/mage/client/util/gui/ArrowBuilder.java
index 1c19bd5eca0..3520af3b4c5 100644
--- a/Mage.Client/src/main/java/mage/client/util/gui/ArrowBuilder.java
+++ b/Mage.Client/src/main/java/mage/client/util/gui/ArrowBuilder.java
@@ -45,16 +45,12 @@ public class ArrowBuilder {
      * Get the panel where all arrows are being drawn.
      * @return
      */
-    public JPanel getArrowsManagerPanel() {
+    public synchronized JPanel getArrowsManagerPanel() {
         if (arrowsManagerPanel == null) {
-            synchronized (ArrowBuilder.class) {
-                if (arrowsManagerPanel == null) {
-                    arrowsManagerPanel = new JPanel();
-                    arrowsManagerPanel.setVisible(true);
-                    arrowsManagerPanel.setOpaque(false);
-                    arrowsManagerPanel.setLayout(null);
-                }
-            }
+            arrowsManagerPanel = new JPanel();
+            arrowsManagerPanel.setVisible(true);
+            arrowsManagerPanel.setOpaque(false);
+            arrowsManagerPanel.setLayout(null);
         }
         return arrowsManagerPanel;
     }