diff -r 27a0fdd7bca7 -r fb30f7b78f9b src/main/java/de/uapcore/lightpit/dao/UserDao.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/de/uapcore/lightpit/dao/UserDao.java	Sat May 09 14:37:15 2020 +0200
@@ -0,0 +1,80 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ * 
+ * Copyright 2018 Mike Becker. All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+package de.uapcore.lightpit.dao;
+
+import de.uapcore.lightpit.entities.User;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class UserDao {
+
+    /**
+     * Maps SQL columns to POJO fields.
+     *
+     * @param result the database result set
+     * @param user   the POJO
+     * @throws SQLException
+     */
+    protected void mapColumns(ResultSet result, User user) throws SQLException {
+        user.setUserID(result.getInt("userid"));
+        user.setUsername(result.getString("username"));
+        user.setGivenname(Optional.ofNullable(result.getString("givenname")));
+        user.setLastname(Optional.ofNullable(result.getString("lastname"))); 
+    }
+
+    /**
+     * Returns a list of all users ordered by their username.
+     * 
+     * Does not return reserved system users with negative user IDs.
+     * 
+     * @param conn the connection to use
+     * @return a list of all users
+     * @throws SQLException 
+     */
+    public List<User> listAll(Connection conn) throws SQLException {
+        List<User> list = new ArrayList<>();
+        try (
+                Statement stmt = conn.createStatement();
+                ResultSet result = stmt.executeQuery(
+                        "SELECT * FROM lpitcore_user WHERE userid >= 0 ORDER BY username")) {
+            while (result.next()) {
+                final User user = new User();
+                mapColumns(result, user);
+                list.add(user);
+            }
+        }
+        return list;
+    }
+}