Refactor code a little bit.

src/main/java/org/appledash/saneeconomy/command/SaneEconomyCommand.java

@@ -20,7 +20,7 @@ public abstract class SaneEconomyCommand implements CommandExecutor {
                 throw new NoPermissionException();
             }
 
-            return onCommand(sender, args);
+            onCommand(sender, args);
         } catch (UsageException e) {
             /* Invalid usage in some way, print out exactly what went wrong along with the proper usage. */
             MessageUtils.sendMessage(sender, e.getMessage());
@@ -28,12 +28,11 @@ public abstract class SaneEconomyCommand implements CommandExecutor {
             for (String s : getUsage()) {
                 MessageUtils.sendMessage(sender, String.format("Usage: %s", s.replace("<command>", label)));
             }
-            
-            return true;
         } catch (CommandException e) {
             MessageUtils.sendMessage(sender, e.getMessage());
-            return true;
         }
+
+        return true;
     }
 
     /**
@@ -49,5 +48,5 @@ public abstract class SaneEconomyCommand implements CommandExecutor {
      */
     public abstract String[] getUsage();
 
-    protected abstract boolean onCommand(CommandSender sender, String[] args) throws CommandException;
+    protected abstract void onCommand(CommandSender sender, String[] args) throws CommandException;
 }

src/main/java/org/appledash/saneeconomy/command/type/BalanceCommand.java

@@ -27,7 +27,7 @@ public class BalanceCommand extends SaneEconomyCommand {
     }
 
     @Override
-    public boolean onCommand(CommandSender sender, String[] args) throws CommandException {
+    public void onCommand(CommandSender sender, String[] args) throws CommandException {
         String playerName;
 
         if (args.length == 0) {
@@ -44,11 +44,11 @@ public class BalanceCommand extends SaneEconomyCommand {
 
         if (player == null) {
             MessageUtils.sendMessage(sender, "That player is not online.");
-            return true;
+            return;
         }
 
         MessageUtils.sendMessage(sender, "Balance of %s is %s.", playerName, SaneEconomy.getInstance().getEconomyManager().getFormattedBalance(player));
 
-        return true;
+        return;
     }
 }

src/main/java/org/appledash/saneeconomy/command/type/EconomyAdminCommand.java

@@ -30,7 +30,7 @@ public class EconomyAdminCommand extends SaneEconomyCommand {
     }
 
     @Override
-    public boolean onCommand(CommandSender sender, String[] args) throws CommandException {
+    public void onCommand(CommandSender sender, String[] args) throws CommandException {
         if (args.length < 2) {
             throw new TooFewArgumentsException();
         }
@@ -55,7 +55,7 @@ public class EconomyAdminCommand extends SaneEconomyCommand {
 
         if (targetPlayer == null) {
             MessageUtils.sendMessage(sender, "That player is not online.");
-            return true;
+            return;
         }
 
         double amount;
@@ -68,7 +68,7 @@ public class EconomyAdminCommand extends SaneEconomyCommand {
             }
         } catch (NumberFormatException e) {
             MessageUtils.sendMessage(sender, "%s is not a positive number.", sAmount);
-            return true;
+            return;
         }
 
         EconomyManager ecoMan = SaneEconomy.getInstance().getEconomyManager();
@@ -81,7 +81,7 @@ public class EconomyAdminCommand extends SaneEconomyCommand {
                     sTargetPlayer,
                     ecoMan.getCurrency().formatAmount(newAmount)
             );
-            return true;
+            return;
         } else if (subCommand.equalsIgnoreCase("take")) {
             double newAmount = ecoMan.subtractBalance(targetPlayer, amount);
 
@@ -90,11 +90,11 @@ public class EconomyAdminCommand extends SaneEconomyCommand {
                     sTargetPlayer,
                     ecoMan.getCurrency().formatAmount(newAmount)
             );
-            return true;
+            return;
         } else if (subCommand.equalsIgnoreCase("set")) {
             ecoMan.setBalance(targetPlayer, amount);
             MessageUtils.sendMessage(sender, "Balance for %s set to %s", sTargetPlayer, ecoMan.getCurrency().formatAmount(amount));
-            return true;
+            return;
         }
 
         throw new InvalidUsageException();

src/main/java/org/appledash/saneeconomy/economy/Currency.java

@@ -11,11 +11,11 @@ import java.text.DecimalFormat;
  * Represents an in-game currency.
  */
 public class Currency {
-    private String nameSingular;
-    private String namePlural;
-    private DecimalFormat format;
+    private final String nameSingular;
+    private final String namePlural;
+    private final DecimalFormat format;
 
-    public Currency(String nameSingular, String namePlural, DecimalFormat format) {
+    private Currency(String nameSingular, String namePlural, DecimalFormat format) {
         this.nameSingular = nameSingular;
         this.namePlural = namePlural;
         this.format = format;

src/main/java/org/appledash/saneeconomy/economy/EconomyManager.java

@@ -10,8 +10,8 @@ import org.bukkit.entity.Player;
  * Represents our EconomyManager, which manages players' balances.
  */
 public class EconomyManager {
-    private Currency currency;
-    private EconomyStorageBackend backend;
+    private final Currency currency;
+    private final EconomyStorageBackend backend;
 
     public EconomyManager(Currency currency, EconomyStorageBackend backend) {
         this.currency = currency;

src/main/java/org/appledash/saneeconomy/economy/backend/type/EconomyStorageBackendFlatfile.java

@@ -16,7 +16,7 @@ import java.util.UUID;
 public class EconomyStorageBackendFlatfile implements EconomyStorageBackend {
     private static final int SCHEMA_VERSION = 1;
 
-    private File file;
+    private final File file;
     private Map<UUID, Double> playerBalances = new HashMap<>();
 
     public EconomyStorageBackendFlatfile(File file) {

src/main/java/org/appledash/saneeconomy/listeners/JoinQuitListener.java

@@ -12,7 +12,7 @@ import org.bukkit.event.player.PlayerJoinEvent;
  * Blackjack is still best pony.
  */
 public class JoinQuitListener implements Listener {
-    private SaneEconomy plugin;
+    private final SaneEconomy plugin;
 
     public JoinQuitListener(SaneEconomy plugin) {
         this.plugin = plugin;
@@ -22,7 +22,7 @@ public class JoinQuitListener implements Listener {
     public void onPlayerJoin(PlayerJoinEvent evt) {
         Player player = evt.getPlayer();
         double startBalance = plugin.getConfig().getDouble("economy.start-balance", 0.0D);
-        
+
         /* A starting balance is configured AND they haven't been given it yet. */
         if (startBalance > 0 && !plugin.getEconomyManager().accountExists(player)) {
             plugin.getEconomyManager().setBalance(player, startBalance);

src/main/java/org/appledash/saneeconomy/utils/MessageUtils.java

@@ -18,6 +18,6 @@ public class MessageUtils {
      */
     public static void sendMessage(CommandSender target, String fmt, String... args) {
         String prefix = ChatColor.translateAlternateColorCodes('&', SaneEconomy.getInstance().getConfig().getString("chat.prefix", ""));
-        target.sendMessage(prefix + String.format(fmt, args));
+        target.sendMessage(prefix + String.format(fmt, (Object[])args));
     }
 }