All 1-character strings converted to primitives

"b" + "r" now changed to 'b' + 'w'.  It's more straight-forward, and may cause perfomance improvements - character primitives allocation is faster and less expensive than string creation.

Mage.Client/src/main/java/mage/client/util/CardsViewUtil.java

@@ -59,7 +59,7 @@ public class CardsViewUtil {
         CardsView cards = new CardsView();
 
         for (SimpleCardView simple: view.values()) {
-            String key = simple.getExpansionSetCode() + "_" + simple.getCardNumber();
+            String key = simple.getExpansionSetCode() + '_' + simple.getCardNumber();
             Card card = loadedCards.get(key);
             if(card == null)
             {

Mage.Client/src/main/java/mage/client/util/Format.java

@@ -62,13 +62,13 @@ public class Format {
         seconds = seconds % 3600;
         long m = seconds / 60;
         long s = seconds % 60;
-        sb.append(h).append(":");
+        sb.append(h).append(':');
         if (m<10) {
-            sb.append("0");
+            sb.append('0');
         }
-        sb.append(m).append(":");
+        sb.append(m).append(':');
         if (s<10) {
-            sb.append("0");
+            sb.append('0');
         }
         sb.append(s);
         return sb.toString();

Mage.Client/src/main/java/mage/client/util/audio/MusicPlayer.java

@@ -112,7 +112,7 @@ public class MusicPlayer {
                 volume = (FloatControl) sourceDataLine.getControl(FloatControl.Type.MASTER_GAIN);
                 sourceDataLine.start();
             } catch (Exception e) {
-                log.error("Couldn't load file: " + file + " " + e);
+                log.error("Couldn't load file: " + file + ' ' + e);
             }
 
         }

Mage.Client/src/main/java/mage/client/util/gui/GuiDisplayUtil.java

@@ -222,7 +222,7 @@ public class GuiDisplayUtil {
         buffer.append("<tr><td valign='top'><b>");
         buffer.append(card.getDisplayName());
         if (card.isGameObject()) {
-            buffer.append(" [").append(card.getId().toString().substring(0, 3)).append("]");
+            buffer.append(" [").append(card.getId().toString().substring(0, 3)).append(']');
         }
         buffer.append("</b></td><td align='right' valign='top' style='width:");
         buffer.append(symbolCount * GUISizeHelper.cardTooltipFontSize);
@@ -232,7 +232,7 @@ public class GuiDisplayUtil {
         }
         buffer.append("</td></tr></table>");
         buffer.append("<table cellspacing=0 cellpadding=0 border=0 width='100%'><tr><td style='margin-left: 1px'>");
-        String imageSize = " width=" + GUISizeHelper.cardTooltipFontSize + " height=" + GUISizeHelper.cardTooltipFontSize + ">";
+        String imageSize = " width=" + GUISizeHelper.cardTooltipFontSize + " height=" + GUISizeHelper.cardTooltipFontSize + '>';
         if (card.getColor().isWhite()) {
             buffer.append("<img src='").append(getResourcePath("card/color_ind_white.png")).append("' alt='W' ").append(imageSize);
         }
@@ -281,7 +281,7 @@ public class GuiDisplayUtil {
 
         String pt = "";
         if (CardUtil.isCreature(card)) {
-            pt = card.getPower() + "/" + card.getToughness();
+            pt = card.getPower() + '/' + card.getToughness();
         } else if (CardUtil.isPlaneswalker(card)) {
             pt = card.getLoyalty();
         }
@@ -291,7 +291,7 @@ public class GuiDisplayUtil {
         buffer.append("<td align='right'>");
         if (!card.isControlledByOwner()) {
             if (card instanceof PermanentView) {
-                buffer.append("[").append(((PermanentView) card).getNameOwner()).append("] ");
+                buffer.append('[').append(((PermanentView) card).getNameOwner()).append("] ");
             } else {
                 buffer.append("[only controlled] ");
             }
@@ -361,16 +361,16 @@ public class GuiDisplayUtil {
     private static String getTypes(CardView card) {
         String types = "";
         for (String superType : card.getSuperTypes()) {
-            types += superType + " ";
+            types += superType + ' ';
         }
         for (CardType cardType : card.getCardTypes()) {
-            types += cardType.toString() + " ";
+            types += cardType.toString() + ' ';
         }
         if (card.getSubTypes().size() > 0) {
             types += "- ";
         }
         for (String subType : card.getSubTypes()) {
-            types += subType + " ";
+            types += subType + ' ';
         }
         return types.trim();
     }

Mage.Client/src/main/java/mage/client/util/gui/TableUtil.java

@@ -59,8 +59,8 @@ public class TableUtil {
         for (int i = 0; i < table.getColumnModel().getColumnCount(); i++) {
             TableColumn column = table.getColumnModel().getColumn(table.convertColumnIndexToView(i));
             if (!firstValue) {
-                columnWidthSettings.append(",");
-                columnOrderSettings.append(",");
+                columnWidthSettings.append(',');
+                columnOrderSettings.append(',');
             } else {
                 firstValue = false;
             }

Mage.Client/src/main/java/mage/client/util/gui/countryBox/MyComboBoxEditor.java

@@ -65,7 +65,7 @@ public class MyComboBoxEditor extends BasicComboBoxEditor {
      
     @Override
     public Object getItem() {
-        return "[" + this.selectedItem.toString() + "]";
+        return '[' + this.selectedItem.toString() + ']';
     }
      
     @Override

Mage.Client/src/main/java/mage/client/util/object/SaveObjectUtil.java

@@ -53,7 +53,7 @@ public class SaveObjectUtil {
                     }
                 }
                 String time = now(DATE_PATTERN);
-                File f = new File("income" + File.separator + name + "_" + time + ".save");
+                File f = new File("income" + File.separator + name + '_' + time + ".save");
                 if (!f.exists()) {
                     f.createNewFile();
                 }