✨ Added CommandExecutionException which wraps any exception thrown during the execution of command handlers. Should be handled using CommandManager#registerExceptionHandler, similar to NoSuchCommandException, ArgumentParseException, etc.

CHANGELOG.md

@@ -14,6 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  - Added a method to get the failure reason of SelectorParseExceptions
  - Added some methods to FlagContext to work with flag values as optionals
  - Allow for use of named suggestion providers with `@Flag`s (cloud-annotations)
+ - Added `CommandExecutionException` which wraps any exception thrown during the execution of command handlers. Should be
+  handled using `CommandManager#registerExceptionHandler`, similar to `NoSuchCommandException`, `ArgumentParseException`, etc.
  
 ### Changed
  - Allow for use of `@Completions` annotation with argument types other than String

cloud-annotations/src/main/java/cloud/commandframework/annotations/MethodCommandExecutionHandler.java

@@ -28,6 +28,7 @@ import cloud.commandframework.annotations.injection.ParameterInjectorRegistry;
 import cloud.commandframework.arguments.CommandArgument;
 import cloud.commandframework.arguments.flags.FlagContext;
 import cloud.commandframework.context.CommandContext;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.execution.CommandExecutionHandler;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
@@ -115,8 +116,10 @@ class MethodCommandExecutionHandler<C> implements CommandExecutionHandler<C> {
         /* Invoke the command method */
         try {
             this.methodHandle.invokeWithArguments(arguments);
-        } catch (final Throwable e) {
+        } catch (final Error e) {
-            e.printStackTrace();
+            throw e;
+        } catch (final Throwable throwable) {
+            throw new CommandExecutionException(throwable);
         }
     }
 

cloud-core/src/main/java/cloud/commandframework/exceptions/CommandExecutionException.java

@@ -0,0 +1,46 @@
+//
+// MIT License
+//
+// Copyright (c) 2020 Alexander Söderberg & Contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+package cloud.commandframework.exceptions;
+
+import org.checkerframework.checker.nullness.qual.NonNull;
+
+/**
+ * Exception thrown when there is an exception during execution of a command handler
+ *
+ * @since 1.2.0
+ */
+public class CommandExecutionException extends IllegalArgumentException {
+
+    private static final long serialVersionUID = -4785446899438294661L;
+
+    /**
+     * Exception thrown when there is an exception during execution of a command handler
+     *
+     * @param cause Exception thrown during the execution of a command handler
+     */
+    public CommandExecutionException(final @NonNull Throwable cause) {
+        super(cause);
+    }
+
+}

cloud-core/src/main/java/cloud/commandframework/execution/AsynchronousCommandExecutionCoordinator.java

@@ -27,6 +27,7 @@ import cloud.commandframework.Command;
 import cloud.commandframework.CommandManager;
 import cloud.commandframework.CommandTree;
 import cloud.commandframework.context.CommandContext;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.services.State;
 import cloud.commandframework.types.tuples.Pair;
 import org.checkerframework.checker.nullness.qual.NonNull;
@@ -76,10 +77,17 @@ public final class AsynchronousCommandExecutionCoordinator<C> extends CommandExe
             final @NonNull CommandContext<C> commandContext,
             final @NonNull Queue<@NonNull String> input
     ) {
+        final CompletableFuture<CommandResult<C>> resultFuture = new CompletableFuture<>();
 
         final Consumer<Command<C>> commandConsumer = command -> {
             if (this.commandManager.postprocessContext(commandContext, command) == State.ACCEPTED) {
+                try {
                     command.getCommandExecutionHandler().execute(commandContext);
+                } catch (final CommandExecutionException exception) {
+                    resultFuture.completeExceptionally(exception);
+                } catch (final Exception exception) {
+                    resultFuture.completeExceptionally(new CommandExecutionException(exception));
+                }
             }
         };
 
@@ -97,8 +105,6 @@ public final class AsynchronousCommandExecutionCoordinator<C> extends CommandExe
             }, this.executor);
         }
 
-        final CompletableFuture<CommandResult<C>> resultFuture = new CompletableFuture<>();
-
         this.executor.execute(() -> {
             try {
                 final @NonNull Pair<@Nullable Command<C>, @Nullable Exception> pair =

cloud-core/src/main/java/cloud/commandframework/execution/CommandExecutionCoordinator.java

@@ -26,6 +26,7 @@ package cloud.commandframework.execution;
 import cloud.commandframework.Command;
 import cloud.commandframework.CommandTree;
 import cloud.commandframework.context.CommandContext;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.services.State;
 import cloud.commandframework.types.tuples.Pair;
 import org.checkerframework.checker.nullness.qual.NonNull;
@@ -103,7 +104,7 @@ public abstract class CommandExecutionCoordinator<C> {
         }
 
         @Override
-        public CompletableFuture<CommandResult<C>> coordinateExecution(
+        public @NonNull CompletableFuture<CommandResult<C>> coordinateExecution(
                 final @NonNull CommandContext<C> commandContext,
                 final @NonNull Queue<@NonNull String> input
         ) {
@@ -116,7 +117,13 @@ public abstract class CommandExecutionCoordinator<C> {
                 } else {
                     final Command<C> command = Objects.requireNonNull(pair.getFirst());
                     if (this.getCommandTree().getCommandManager().postprocessContext(commandContext, command) == State.ACCEPTED) {
+                        try {
                             command.getCommandExecutionHandler().execute(commandContext);
+                        } catch (final CommandExecutionException exception) {
+                            completableFuture.completeExceptionally(exception);
+                        } catch (final Exception exception) {
+                            completableFuture.completeExceptionally(new CommandExecutionException(exception));
+                        }
                     }
                     completableFuture.complete(new CommandResult<>(commandContext));
                 }

cloud-discord/cloud-javacord/src/main/java/cloud/commandframework/javacord/JavacordCommand.java

@@ -26,6 +26,7 @@ package cloud.commandframework.javacord;
 import cloud.commandframework.arguments.CommandArgument;
 import cloud.commandframework.arguments.StaticArgument;
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -42,6 +43,7 @@ import java.util.concurrent.CompletionException;
 
 public class JavacordCommand<C> implements MessageCreateListener {
 
+    private static final String MESSAGE_INTERNAL_ERROR = "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_NO_PERMS = "I'm sorry, but you do not have the permission to do this :/";
 
     private final JavacordCommandManager<C> manager;
@@ -95,6 +97,7 @@ public class JavacordCommand<C> implements MessageCreateListener {
                     if (throwable == null) {
                         return;
                     }
+                    final Throwable finalThrowable = throwable;
 
                     if (throwable instanceof CompletionException) {
                         throwable = throwable.getCause();
@@ -153,6 +156,20 @@ public class JavacordCommand<C> implements MessageCreateListener {
                         return;
                     }
 
+                    if (throwable instanceof CommandExecutionException) {
+                        manager.handleException(
+                                sender,
+                                CommandExecutionException.class,
+                                (CommandExecutionException) throwable,
+                                (c, e) -> {
+                                    commandSender.sendErrorMessage(MESSAGE_INTERNAL_ERROR);
+                                    finalThrowable.getCause().printStackTrace();
+                                }
+                        );
+
+                        return;
+                    }
+
                     commandSender.sendErrorMessage(throwable.getMessage());
                     throwable.printStackTrace();
                 });

cloud-discord/cloud-jda/src/main/java/cloud/commandframework/jda/JDACommandListener.java

@@ -24,6 +24,7 @@
 package cloud.commandframework.jda;
 
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -41,6 +42,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 @SuppressWarnings("deprecation")
 public class JDACommandListener<C> extends ListenerAdapter {
 
+    private static final String MESSAGE_INTERNAL_ERROR = "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_INVALID_SYNTAX = "Invalid Command Syntax. Correct command syntax is: ";
     private static final String MESSAGE_NO_PERMS = "I'm sorry, but you do not have permission to perform this command. "
             + "Please contact the server administrators if you believe that this is in error.";
@@ -116,6 +118,16 @@ public class JDACommandListener<C> extends ListenerAdapter {
                                                 .getMessage()
                                 )
                         );
+                    } else if (throwable instanceof CommandExecutionException) {
+                        this.commandManager.handleException(sender, CommandExecutionException.class,
+                                (CommandExecutionException) throwable, (c, e) -> {
+                                    this.sendMessage(
+                                            event,
+                                            MESSAGE_INTERNAL_ERROR
+                                    );
+                                    throwable.getCause().printStackTrace();
+                                }
+                        );
                     } else {
                         this.sendMessage(event, throwable.getMessage());
                     }

cloud-irc/cloud-pircbotx/src/main/java/cloud/commandframework/pircbotx/CloudListenerAdapter.java

@@ -24,6 +24,7 @@
 package cloud.commandframework.pircbotx;
 
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -34,6 +35,7 @@ import org.pircbotx.hooks.types.GenericMessageEvent;
 
 final class CloudListenerAdapter<C> extends ListenerAdapter {
 
+    private static final String MESSAGE_INTERNAL_ERROR = "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_INVALID_SYNTAX = "Invalid Command Syntax. Correct command syntax is: ";
     private static final String MESSAGE_NO_PERMS = "I'm sorry, but you do not have permission to perform this command. "
             + "Please contact the server administrators if you believe that this is in error.";
@@ -57,6 +59,7 @@ final class CloudListenerAdapter<C> extends ListenerAdapter {
                     if (throwable == null) {
                         return;
                     }
+                    final Throwable finalThrowable = throwable;
 
                     if (throwable instanceof InvalidSyntaxException) {
                         this.manager.handleException(sender,
@@ -90,6 +93,13 @@ final class CloudListenerAdapter<C> extends ListenerAdapter {
                                         "Invalid Command Argument: " + throwable.getCause().getMessage()
                                 )
                         );
+                    } else if (throwable instanceof CommandExecutionException) {
+                        this.manager.handleException(sender, CommandExecutionException.class,
+                                (CommandExecutionException) throwable, (c, e) -> {
+                                    event.respondWith(MESSAGE_INTERNAL_ERROR);
+                                    finalThrowable.getCause().printStackTrace();
+                                }
+                        );
                     } else {
                         event.respondWith(throwable.getMessage());
                     }

cloud-minecraft/cloud-bukkit/src/main/java/cloud/commandframework/bukkit/BukkitCommand.java

@@ -26,6 +26,7 @@ package cloud.commandframework.bukkit;
 import cloud.commandframework.Command;
 import cloud.commandframework.arguments.CommandArgument;
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -38,9 +39,12 @@ import org.checkerframework.checker.nullness.qual.NonNull;
 
 import java.util.List;
 import java.util.concurrent.CompletionException;
+import java.util.logging.Level;
 
 final class BukkitCommand<C> extends org.bukkit.command.Command implements PluginIdentifiableCommand {
 
+    private static final String MESSAGE_INTERNAL_ERROR = ChatColor.RED
+            + "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_NO_PERMS = ChatColor.RED
             + "I'm sorry, but you do not have permission to perform this command. "
             + "Please contact the server administrators if you believe that this is in error.";
@@ -50,7 +54,6 @@ final class BukkitCommand<C> extends org.bukkit.command.Command implements Plugi
     private final BukkitCommandManager<C> manager;
     private final Command<C> cloudCommand;
 
-    @SuppressWarnings("unchecked")
     BukkitCommand(
             final @NonNull String label,
             final @NonNull List<@NonNull String> aliases,
@@ -133,9 +136,25 @@ final class BukkitCommand<C> extends org.bukkit.command.Command implements Plugi
                                                             + ChatColor.GRAY + finalThrowable.getCause()
                                                             .getMessage())
                             );
+                        } else if (throwable instanceof CommandExecutionException) {
+                            this.manager.handleException(sender,
+                                    CommandExecutionException.class,
+                                    (CommandExecutionException) throwable, (c, e) -> {
+                                        commandSender.sendMessage(MESSAGE_INTERNAL_ERROR);
+                                        this.manager.getOwningPlugin().getLogger().log(
+                                                Level.SEVERE,
+                                                "Exception executing command handler",
+                                                finalThrowable.getCause()
+                                        );
+                                    }
+                            );
                         } else {
-                            commandSender.sendMessage(throwable.getMessage());
+                            commandSender.sendMessage(MESSAGE_INTERNAL_ERROR);
-                            throwable.printStackTrace();
+                            this.manager.getOwningPlugin().getLogger().log(
+                                    Level.SEVERE,
+                                    "An unhandled exception was thrown during command execution",
+                                    throwable
+                            );
                         }
                     }
                 });

cloud-minecraft/cloud-bungee/src/main/java/cloud/commandframework/bungee/BungeeCommand.java

@@ -26,6 +26,7 @@ package cloud.commandframework.bungee;
 import cloud.commandframework.arguments.CommandArgument;
 import cloud.commandframework.arguments.StaticArgument;
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -38,9 +39,11 @@ import net.md_5.bungee.api.plugin.TabExecutor;
 import org.checkerframework.checker.nullness.qual.NonNull;
 
 import java.util.concurrent.CompletionException;
+import java.util.logging.Level;
 
 public final class BungeeCommand<C> extends Command implements TabExecutor {
 
+    private static final String MESSAGE_INTERNAL_ERROR = "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_NO_PERMS =
             "I'm sorry, but you do not have permission to perform this command. "
                     + "Please contact the server administrators if you believe that this is in error.";
@@ -138,18 +141,27 @@ public final class BungeeCommand<C> extends Command implements TabExecutor {
                                                             .getMessage())
                                                     .create())
                             );
-                        } else {
+                        } else if (throwable instanceof CommandExecutionException) {
-                            commandSender.sendMessage(new ComponentBuilder(throwable.getMessage()).create());
+                            this.manager.handleException(sender,
-                            this.manager.getOwningPlugin().getLogger().warning(
+                                    CommandExecutionException.class,
-                                    String.format(
+                                    (CommandExecutionException) throwable, (c, e) -> {
-                                            "(Cloud) Unknown exception type '%s' with cause '%s'",
+                                        commandSender.sendMessage(new ComponentBuilder(MESSAGE_INTERNAL_ERROR)
-                                            throwable.getClass().getCanonicalName(),
+                                                .color(ChatColor.RED)
-                                            throwable.getCause() == null ? "none"
+                                                .create());
-                                                    : throwable.getCause()
+                                        this.manager.getOwningPlugin().getLogger().log(
-                                                            .getClass().getCanonicalName()
+                                                Level.SEVERE,
-                                    )
+                                                "Exception executing command handler",
+                                                finalThrowable.getCause()
+                                        );
+                                    }
+                            );
+                        } else {
+                            commandSender.sendMessage(new ComponentBuilder(MESSAGE_INTERNAL_ERROR).color(ChatColor.RED).create());
+                            this.manager.getOwningPlugin().getLogger().log(
+                                    Level.SEVERE,
+                                    "An unhandled exception was thrown during command execution",
+                                    throwable
                             );
-                            throwable.printStackTrace();
                         }
                     }
                 });

cloud-minecraft/cloud-cloudburst/src/main/java/cloud/commandframework/cloudburst/CloudburstCommand.java

@@ -26,6 +26,7 @@ package cloud.commandframework.cloudburst;
 import cloud.commandframework.Command;
 import cloud.commandframework.arguments.CommandArgument;
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -41,6 +42,7 @@ import java.util.concurrent.CompletionException;
 
 final class CloudburstCommand<C> extends PluginCommand<Plugin> {
 
+    private static final String MESSAGE_INTERNAL_ERROR = "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_NO_PERMS =
             "I'm sorry, but you do not have permission to perform this command. "
                     + "Please contact the server administrators if you believe that this is in error.";
@@ -124,9 +126,23 @@ final class CloudburstCommand<C> extends PluginCommand<Plugin> {
                                                     "Invalid Command Argument: "
                                                             + finalThrowable.getCause().getMessage())
                             );
+                        } else if (throwable instanceof CommandExecutionException) {
+                            this.manager.handleException(sender,
+                                    CommandExecutionException.class,
+                                    (CommandExecutionException) throwable, (c, e) -> {
+                                        commandSender.sendMessage(MESSAGE_INTERNAL_ERROR);
+                                        manager.getOwningPlugin().getLogger().error(
+                                                "Exception executing command handler",
+                                                finalThrowable.getCause()
+                                        );
+                                    }
+                            );
                         } else {
-                            commandSender.sendMessage(throwable.getMessage());
+                            commandSender.sendMessage(MESSAGE_INTERNAL_ERROR);
-                            throwable.printStackTrace();
+                            manager.getOwningPlugin().getLogger().error(
+                                    "An unhandled exception was thrown during command execution",
+                                    throwable
+                            );
                         }
                     }
                 });

cloud-minecraft/cloud-minecraft-extras/src/main/java/cloud/commandframework/minecraft/extras/MinecraftExceptionHandler.java

@@ -25,6 +25,7 @@ package cloud.commandframework.minecraft.extras;
 
 import cloud.commandframework.CommandManager;
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -89,6 +90,19 @@ public final class MinecraftExceptionHandler<C> {
                     .append(Component.text("Invalid command argument: ", NamedTextColor.RED))
                     .append(Component.text(e.getCause().getMessage(), NamedTextColor.GRAY))
                     .build();
+    /**
+     * Default component builder for {@link CommandExecutionException}
+     *
+     * @since 1.2.0
+     */
+    public static final Function<Exception, Component> DEFAULT_COMMAND_EXECUTION_FUNCTION =
+            e -> {
+                e.getCause().printStackTrace();
+                return Component.text()
+                        .append(Component.text("An internal error occurred while attempting to perform this command.",
+                                NamedTextColor.RED))
+                        .build();
+            };
 
     private final Map<ExceptionType, BiFunction<C, Exception, Component>> componentBuilders = new HashMap<>();
     private Function<Component, Component> decorator = Function.identity();
@@ -130,7 +144,17 @@ public final class MinecraftExceptionHandler<C> {
     }
 
     /**
-     * Use all four of the default exception handlers
+     * Use the default {@link CommandExecutionException} handler
+     *
+     * @return {@code this}
+     * @since 1.2.0
+     */
+    public @NonNull MinecraftExceptionHandler<C> withCommandExecutionHandler() {
+        return this.withHandler(ExceptionType.COMMAND_EXECUTION, DEFAULT_COMMAND_EXECUTION_FUNCTION);
+    }
+
+    /**
+     * Use all of the default exception handlers
      *
      * @return {@code this}
      */
@@ -139,7 +163,8 @@ public final class MinecraftExceptionHandler<C> {
                 .withArgumentParsingHandler()
                 .withInvalidSenderHandler()
                 .withInvalidSyntaxHandler()
-                .withNoPermissionHandler();
+                .withNoPermissionHandler()
+                .withCommandExecutionHandler();
     }
 
     /**
@@ -237,6 +262,15 @@ public final class MinecraftExceptionHandler<C> {
                     )
             );
         }
+        if (componentBuilders.containsKey(ExceptionType.COMMAND_EXECUTION)) {
+            manager.registerExceptionHandler(
+                    CommandExecutionException.class,
+                    (c, e) -> audienceMapper.apply(c).sendMessage(
+                            Identity.nil(),
+                            this.decorator.apply(this.componentBuilders.get(ExceptionType.COMMAND_EXECUTION).apply(c, e))
+                    )
+            );
+        }
     }
 
 
@@ -259,7 +293,13 @@ public final class MinecraftExceptionHandler<C> {
         /**
          * An argument failed to parse ({@link ArgumentParseException})
          */
-        ARGUMENT_PARSING
+        ARGUMENT_PARSING,
+        /**
+         * A command handler had an exception ({@link CommandExecutionException})
+         *
+         * @since 1.2.0
+         */
+        COMMAND_EXECUTION
     }
 
 }

cloud-minecraft/cloud-velocity/src/main/java/cloud/commandframework/velocity/VelocityExecutor.java

@@ -24,6 +24,7 @@
 package cloud.commandframework.velocity;
 
 import cloud.commandframework.exceptions.ArgumentParseException;
+import cloud.commandframework.exceptions.CommandExecutionException;
 import cloud.commandframework.exceptions.InvalidCommandSenderException;
 import cloud.commandframework.exceptions.InvalidSyntaxException;
 import cloud.commandframework.exceptions.NoPermissionException;
@@ -42,6 +43,7 @@ import java.util.function.BiConsumer;
 
 final class VelocityExecutor<C> implements Command<CommandSource> {
 
+    private static final String MESSAGE_INTERNAL_ERROR = "An internal error occurred while attempting to perform this command.";
     private static final String MESSAGE_NO_PERMS =
             "I'm sorry, but you do not have permission to perform this command. "
                     + "Please contact the server administrators if you believe that this is in error.";
@@ -128,8 +130,7 @@ final class VelocityExecutor<C> implements Command<CommandSource> {
                             sender,
                             ArgumentParseException.class,
                             (ArgumentParseException) throwable,
-                            (c, e) ->
+                            (c, e) -> source.sendMessage(
-                                    source.sendMessage(
                                     Identity.nil(),
                                     Component.text()
                                             .append(Component.text(
@@ -142,10 +143,26 @@ final class VelocityExecutor<C> implements Command<CommandSource> {
                                             ))
                             )
                     );
+                } else if (throwable instanceof CommandExecutionException) {
+                    this.manager.handleException(
+                            sender,
+                            CommandExecutionException.class,
+                            (CommandExecutionException) throwable,
+                            (c, e) -> {
+                                source.sendMessage(
+                                        Identity.nil(),
+                                        Component.text(
+                                                MESSAGE_INTERNAL_ERROR,
+                                                NamedTextColor.RED
+                                        )
+                                );
+                                finalThrowable.getCause().printStackTrace();
+                            }
+                    );
                 } else {
                     source.sendMessage(
                             Identity.nil(),
-                            Component.text(throwable.getMessage(), NamedTextColor.RED)
+                            Component.text(MESSAGE_INTERNAL_ERROR, NamedTextColor.RED)
                     );
                     throwable.printStackTrace();
                 }

examples/example-bukkit/src/main/java/cloud/commandframework/examples/bukkit/ExamplePlugin.java

@@ -195,6 +195,7 @@ public final class ExamplePlugin extends JavaPlugin {
                 .withInvalidSenderHandler()
                 .withNoPermissionHandler()
                 .withArgumentParsingHandler()
+                .withCommandExecutionHandler()
                 .withDecorator(
                         component -> Component.text()
                                 .append(Component.text("[", NamedTextColor.DARK_GRAY))