Fix TabComplete suggesting online player names instead of nothing

src/main/java/com/songoda/epicvouchers/commands/CommandForce.java

@@ -5,13 +5,11 @@ import com.songoda.epicvouchers.EpicVouchers;
 import com.songoda.epicvouchers.voucher.Voucher;
 import org.bukkit.Bukkit;
 import org.bukkit.command.CommandSender;
-import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
 
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 public class CommandForce extends AbstractCommand {
     final EpicVouchers instance;
@@ -49,14 +47,23 @@ public class CommandForce extends AbstractCommand {
 
     @Override
     protected List<String> onTab(CommandSender sender, String... args) {
+        List<String> result = new ArrayList<>();
+
         if (args.length == 1) {
-            return Bukkit.getOnlinePlayers().stream().map(HumanEntity::getName).collect(Collectors.toList());
+            for (Player online : Bukkit.getOnlinePlayers()) {
+                result.add(online.getName());
+            }
         } else if (args.length == 2) {
-            return instance.getVoucherManager().getVouchers().stream().map(Voucher::getKey).collect(Collectors.toList());
+            for (Voucher voucher : instance.getVoucherManager().getVouchers()) {
+                result.add(voucher.getKey());
+            }
         } else if (args.length == 3) {
-            return Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10");
+            for (int i = 0; i < 10; ++i) {
+                result.add(String.valueOf(i + 1));
+            }
         }
-        return null;
+
+        return result;
     }
 
     @Override

src/main/java/com/songoda/epicvouchers/commands/CommandForceAll.java

@@ -7,9 +7,7 @@ import org.bukkit.Bukkit;
 import org.bukkit.command.CommandSender;
 
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.List;
-import java.util.stream.Collectors;
 
 public class CommandForceAll extends AbstractCommand {
     final EpicVouchers instance;
@@ -41,12 +39,19 @@ public class CommandForceAll extends AbstractCommand {
 
     @Override
     protected List<String> onTab(CommandSender sender, String... args) {
+        List<String> result = new ArrayList<>();
+
         if (args.length == 1) {
-            return instance.getVoucherManager().getVouchers().stream().map(Voucher::getKey).collect(Collectors.toList());
+            for (Voucher voucher : instance.getVoucherManager().getVouchers()) {
+                result.add(voucher.getKey());
+            }
         } else if (args.length == 2) {
-            return Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10");
+            for (int i = 0; i < 10; ++i) {
+                result.add(String.valueOf(i + 1));
+            }
         }
-        return null;
+
+        return result;
     }
 
     @Override

src/main/java/com/songoda/epicvouchers/commands/CommandGive.java

@@ -5,13 +5,11 @@ import com.songoda.epicvouchers.EpicVouchers;
 import com.songoda.epicvouchers.voucher.Voucher;
 import org.bukkit.Bukkit;
 import org.bukkit.command.CommandSender;
-import org.bukkit.entity.HumanEntity;
 import org.bukkit.entity.Player;
 
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.stream.Collectors;
 
 public class CommandGive extends AbstractCommand {
     final EpicVouchers instance;
@@ -44,14 +42,23 @@ public class CommandGive extends AbstractCommand {
 
     @Override
     protected List<String> onTab(CommandSender sender, String... args) {
+        List<String> result = new ArrayList<>();
+
         if (args.length == 1) {
-            return Bukkit.getOnlinePlayers().stream().map(HumanEntity::getName).collect(Collectors.toList());
+            for (Player online : Bukkit.getOnlinePlayers()) {
+                result.add(online.getName());
+            }
         } else if (args.length == 2) {
-            return instance.getVoucherManager().getVouchers().stream().map(Voucher::getKey).collect(Collectors.toList());
+            for (Voucher voucher : instance.getVoucherManager().getVouchers()) {
+                result.add(voucher.getKey());
+            }
         } else if (args.length == 3) {
-            return Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10");
+            for (int i = 0; i < 10; ++i) {
+                result.add(String.valueOf(i + 1));
+            }
         }
-        return null;
+
+        return result;
     }
 
     @Override

src/main/java/com/songoda/epicvouchers/commands/CommandGiveAll.java

@@ -5,9 +5,8 @@ import com.songoda.epicvouchers.EpicVouchers;
 import com.songoda.epicvouchers.voucher.Voucher;
 import org.bukkit.command.CommandSender;
 
-import java.util.Arrays;
+import java.util.ArrayList;
 import java.util.List;
-import java.util.stream.Collectors;
 
 public class CommandGiveAll extends AbstractCommand {
     final EpicVouchers instance;
@@ -34,12 +33,19 @@ public class CommandGiveAll extends AbstractCommand {
 
     @Override
     protected List<String> onTab(CommandSender sender, String... args) {
+        List<String> result = new ArrayList<>();
+
         if (args.length == 1) {
-            return instance.getVoucherManager().getVouchers().stream().map(Voucher::getKey).collect(Collectors.toList());
+            for (Voucher voucher : instance.getVoucherManager().getVouchers()) {
+                result.add(voucher.getKey());
+            }
         } else if (args.length == 2) {
-            return Arrays.asList("1", "2", "3", "4", "5", "6", "7", "8", "9", "10");
+            for (int i = 0; i < 10; ++i) {
+                result.add(String.valueOf(i + 1));
+            }
         }
-        return null;
+
+        return result;
     }
 
     @Override

src/main/java/com/songoda/epicvouchers/commands/CommandList.java

@@ -6,7 +6,7 @@ import com.songoda.epicvouchers.voucher.Voucher;
 import org.bukkit.command.CommandSender;
 
 import java.util.List;
-import java.util.stream.Collectors;
+import java.util.StringJoiner;
 
 public class CommandList extends AbstractCommand {
     final EpicVouchers instance;
@@ -18,10 +18,15 @@ public class CommandList extends AbstractCommand {
 
     @Override
     protected ReturnType runCommand(CommandSender sender, String... args) {
+        StringJoiner joiner = new StringJoiner(", ");
+        for (Voucher voucher : instance.getVoucherManager().getVouchers()) {
+            joiner.add(voucher.getKey());
+        }
+
         instance.getLocale().getMessage("command.list.list")
-                .processPlaceholder("list",
+                .processPlaceholder("list", joiner.toString())
-                        instance.getVoucherManager().getVouchers().stream().map(Voucher::getKey).collect(Collectors.joining(", ")))
                 .sendPrefixedMessage(sender);
+
         return ReturnType.SUCCESS;
     }