diff --git a/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java b/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java
index 79aa835..88dc150 100644
--- a/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java
+++ b/gclc.system/src/main/java/net/bigeon/gclc/system/ExecSystemCommand.java
@@ -56,6 +56,8 @@ import net.bigeon.gclc.manager.ConsoleOutput;
  * @author Emmanuel Bigeon */
 public class ExecSystemCommand extends Command {
 
+    /** Error message for the manager closed. */
+    private static final String MANAGER_WAS_CLOSED   = "manager was closed";
     /** The command default name */
     private static final String COMMAND_DEFAULT_NAME = "exec";                //$NON-NLS-1$
     /** The end of line separator */
@@ -64,12 +66,14 @@ public class ExecSystemCommand extends Command {
     private static final Logger LOGGER               = Logger
             .getLogger(ExecSystemCommand.class.getName());
 
-    /***/
+    /** Create the command with the name 'exec'. */
     public ExecSystemCommand() {
         super(COMMAND_DEFAULT_NAME);
     }
 
-    /** @param name the name of the command (the input from the manager that should
+    /** Create the command with a custom name.
+     * 
+     * @param name the name of the command (the input from the manager that should
      *        trigger this command) */
     public ExecSystemCommand(final String name) {
         super(name);
@@ -92,7 +96,6 @@ public class ExecSystemCommand extends Command {
         final InputStream is = proc.getInputStream();
         final Thread th = new Thread(new Runnable() {
 
-            @SuppressWarnings("synthetic-access")
             @Override
             public void run() {
                 try {
@@ -110,18 +113,12 @@ public class ExecSystemCommand extends Command {
         final OutputStream os = proc.getOutputStream();
         try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os))) {
             while (th.isAlive()) {
-                String user;
-                try {
-                    user = in.prompt();
-                } catch (final IOException e) {
-                    throw new CommandRunException(CommandRunExceptionType.INTERACTION,
-                            "manager was closed", e); //$NON-NLS-1$
-                }
+                String user = in.prompt();
                 writer.write(user + EOL);
             }
         } catch (final IOException e1) {
             throw new CommandRunException(CommandRunExceptionType.INTERACTION,
-                    "manager was closed", e1); //$NON-NLS-1$
+                    MANAGER_WAS_CLOSED, e1); // $NON-NLS-1$
         }
     }
 
@@ -133,18 +130,28 @@ public class ExecSystemCommand extends Command {
         int c;
         try {
             while ((c = is.read()) != -1) {
-                try {
-                    out.print(Character.valueOf((char) c).toString());
-                } catch (final IOException e) {
-                    throw new CommandRunException(CommandRunExceptionType.INTERACTION,
-                            "manager was closed", e); //$NON-NLS-1$
-                }
+                printCharacter(out, (char) c);
             }
         } catch (final IOException e) {
             LOGGER.log(Level.INFO, "input stream reading failed", e); //$NON-NLS-1$
         }
     }
 
+    /** Print a character on the console.
+     * 
+     * @param out the console
+     * @param c the character
+     * @throws CommandRunException if the console failed to print the character. */
+    private void printCharacter(final ConsoleOutput out, char c)
+            throws CommandRunException {
+        try {
+            out.print(Character.toString(c));
+        } catch (final IOException e) {
+            throw new CommandRunException(CommandRunExceptionType.INTERACTION,
+                    MANAGER_WAS_CLOSED, e); // $NON-NLS-1$
+        }
+    }
+
     /* (non-Javadoc)
      * @see fr.bigeon.gclc.command.ICommand#tip() */
     @Override
diff --git a/gclc.system/src/main/java/net/bigeon/gclc/system/package-info.java b/gclc.system/src/main/java/net/bigeon/gclc/system/package-info.java
new file mode 100644
index 0000000..3af1652
--- /dev/null
+++ b/gclc.system/src/main/java/net/bigeon/gclc/system/package-info.java
@@ -0,0 +1,8 @@
+/** This package contains classes for command execution on the system.
+ * <p>
+ * The class {@link net.bigeon.gclc.system.ExecSystemCommand} is, in the current
+ * version (0.0.1), a source of vulnerability and should probably be used only
+ * in private projects where the user is aware of the dangers.
+ * 
+ * @author Emmanuel Bigeon */
+package net.bigeon.gclc.system;