made some fixes after testing

src/main/java/net/benjidial/nswp/Database.java

@@ -2,6 +2,7 @@ package net.benjidial.nswp;
 
 import org.bukkit.entity.Player;
 import org.bukkit.Location;
+import org.bukkit.OfflinePlayer;
 import org.bukkit.Bukkit;
 
 import java.sql.PreparedStatement;
@@ -23,6 +24,14 @@ public class Database {
     return player.getUniqueId().toString().replaceAll("-", "");
   }
 
+  static OfflinePlayer idToPlayer(String id) {
+    return Bukkit.getOfflinePlayer(UUID.fromString(
+      id.substring( 0,  8) + "-" + id.substring( 8, 12) + "-" +
+      id.substring(12, 16) + "-" + id.substring(16, 20) + "-" +
+      id.substring(20, 32)
+    ));
+  }
+
   static String waypointTableName(Player player) {
     return "waypoints_" + playerID(player);
   }
@@ -124,23 +133,18 @@ public class Database {
   }
 
   public static void addWaypoint(Player player, Waypoint waypoint) throws SQLException {
-    if (lookupWaypoint(player, waypoint.name) != null)
+    PreparedStatement statement = connection.prepareStatement(
-      player.sendMessage("There is already a waypoint with that name.");
+      "INSERT INTO " + waypointTableName(player) + "(name, world, x, y, z, pitch, yaw) " +
-    else {
+      "VALUES(?, ?, ?, ?, ?, ?, ?)"
-      PreparedStatement statement = connection.prepareStatement(
+    );
-        "INSERT INTO " + waypointTableName(player) + "(name, world, x, y, z, pitch, yaw) " +
+    statement.setString(1, waypoint.name);
-        "VALUES(?, ?, ?, ?, ?, ?, ?)"
+    statement.setString(2, waypoint.location.getWorld().getName());
-      );
+    statement.setDouble(3, waypoint.location.getX());
-      statement.setString(1, waypoint.name);
+    statement.setDouble(4, waypoint.location.getY());
-      statement.setString(2, waypoint.location.getWorld().getName());
+    statement.setDouble(5, waypoint.location.getZ());
-      statement.setDouble(3, waypoint.location.getX());
+    statement.setDouble(6, waypoint.location.getPitch());
-      statement.setDouble(4, waypoint.location.getY());
+    statement.setDouble(7, waypoint.location.getYaw());
-      statement.setDouble(5, waypoint.location.getZ());
+    statement.executeUpdate();
-      statement.setDouble(6, waypoint.location.getPitch());
-      statement.setDouble(7, waypoint.location.getYaw());
-      statement.executeUpdate();
-      player.sendMessage("Waypoint added.");
-    }
   }
 
   public static void deleteWaypoint(Player player, String name) throws SQLException {
@@ -148,17 +152,14 @@ public class Database {
       "DELETE FROM " + waypointTableName(player) + " WHERE name = ?"
     );
     statement.setString(1, name);
-    if (statement.executeUpdate() == 0)
+    statement.executeUpdate();
-      player.sendMessage("No waypoint with that name.");
-    else
-      player.sendMessage("Waypoint deleted.");
   }
 
   public static void createTPATable() throws SQLException {
     PreparedStatement statement = connection.prepareStatement(
       "CREATE TABLE IF NOT EXISTS tpa_allowed (" +
-        "from TEXT NOT NULL, " +
+        "from_id TEXT NOT NULL, " +
-        "to   TEXT NOT NULL" +
+        "to_id   TEXT NOT NULL" +
       ")"
     );
     statement.executeUpdate();
@@ -166,7 +167,7 @@ public class Database {
 
   public static boolean isTPAAllowed(Player from, Player to) throws SQLException {
     PreparedStatement statement = connection.prepareStatement(
-      "SELECT * FROM tpa_allowed WHERE from = ? AND to = ?"
+      "SELECT * FROM tpa_allowed WHERE from_id = ? AND to_id = ?"
     );
     statement.setString(1, playerID(from));
     statement.setString(2, playerID(to));
@@ -176,7 +177,7 @@ public class Database {
 
   public static void allowTPA(Player from, Player to) throws SQLException {
     PreparedStatement statement = connection.prepareStatement(
-      "INSERT INTO tpa_allowed(from, to) VALUES(?, ?)"
+      "INSERT INTO tpa_allowed(from_id, to_id) VALUES(?, ?)"
     );
     statement.setString(1, playerID(from));
     statement.setString(2, playerID(to));
@@ -187,7 +188,7 @@ public class Database {
     //this is kinda scrungled but i think it should work.
 
     PreparedStatement statement = connection.prepareStatement(
-      "SELECT * FROM tpa_allowed WHERE to = ?"
+      "SELECT * FROM tpa_allowed WHERE to_id = ?"
     );
     statement.setString(1, playerID(to));
     ResultSet table = statement.executeQuery();
@@ -195,11 +196,11 @@ public class Database {
     int removed = 0;
 
     while (table.next()) {
-      String fromID = table.getString("from");
+      String fromID = table.getString("from_id");
 
-      if (Bukkit.getOfflinePlayer(UUID.fromString(fromID)).getName() == fromName) {
+      if (idToPlayer(fromID).getName().equals(fromName)) {
         PreparedStatement deleteStatement = connection.prepareStatement(
-          "DELETE FROM tpa_allowed WHERE from = ? AND to = ?"
+          "DELETE FROM tpa_allowed WHERE from_id = ? AND to_id = ?"
         );
         deleteStatement.setString(1, fromID);
         deleteStatement.setString(2, playerID(to));
@@ -225,14 +226,14 @@ public class Database {
   public static ArrayList<String> getTPAAllowedTo(Player to) throws SQLException {
 
     PreparedStatement statement = connection.prepareStatement(
-      "SELECT * FROM tpa_allowed WHERE to = ?"
+      "SELECT * FROM tpa_allowed WHERE to_id = ?"
     );
     statement.setString(1, playerID(to));
     ResultSet table = statement.executeQuery();
 
     ArrayList<String> results = new ArrayList<>();
     while (table.next()) {
-      String name = Bukkit.getOfflinePlayer(UUID.fromString(table.getString("from"))).getName();
+      String name = idToPlayer(table.getString("from_id")).getName();
       //there is no way to disallow a player whose name is not know. but, to allow a player,
       //they have to be online, and so their name should be known.
       if (name != null)