Added some comments about exceptions

src/main/java/net/minestom/server/MinecraftServer.java

@@ -595,10 +595,13 @@ public class MinecraftServer {
 
     /**
      * Starts the server.
+     * <p>
+     * It should be called after {@link #init()} and probably your own initialization code.
      *
      * @param address              the server address
      * @param port                 the server port
      * @param responseDataConsumer the response data consumer, can be null
+     * @throws IllegalStateException if called before {@link #init()} or if the server is already running
      */
     public void start(String address, int port, ResponseDataConsumer responseDataConsumer) {
         Check.stateCondition(!initialized, "#start can only be called after #init");
@@ -627,6 +630,7 @@ public class MinecraftServer {
      *
      * @param address the server address
      * @param port    the server port
+     * @see #start(String, int, ResponseDataConsumer)
      */
     public void start(String address, int port) {
         start(address, port, null);

src/main/java/net/minestom/server/chat/ChatColor.java

@@ -242,6 +242,14 @@ public class ChatColor {
         return codeName;
     }
 
+    /**
+     * Gets the color id, only present if this color has been retrieved from {@link ChatColor} constants.
+     * <p>
+     * Should only be used for some special packets which require it.
+     *
+     * @return the color id
+     * @throws IllegalStateException if the color is not from the class constants
+     */
     public int getId() {
         Check.stateCondition(id == -1, "Please use one of the ChatColor constant instead");
         return id;
@@ -263,7 +271,7 @@ public class ChatColor {
             code = codeName;
         } else {
             // RGB color (special code not set)
-            int color = (red & 0xFF) << 16 | (green & 0xFF) << 8 | blue & 0xFF;
+            final int color = (red & 0xFF) << 16 | (green & 0xFF) << 8 | blue & 0xFF;
 
             code = Integer.toHexString(color);
         }

src/main/java/net/minestom/server/entity/Player.java

@@ -1029,6 +1029,7 @@ public class Player extends LivingEntity implements CommandSender {
      * Sets and refresh client food bar.
      *
      * @param food the new food value
+     * @throws IllegalArgumentException if {@code food} is not between 0 and 20
      */
     public void setFood(int food) {
         Check.argCondition(!MathUtils.isBetween(food, 0, 20), "Food has to be between 0 and 20");
@@ -1044,6 +1045,7 @@ public class Player extends LivingEntity implements CommandSender {
      * Sets and refresh client food saturation.
      *
      * @param foodSaturation the food saturation
+     * @throws IllegalArgumentException if {@code foodSaturation} is not between 0 and 5
      */
     public void setFoodSaturation(float foodSaturation) {
         Check.argCondition(!MathUtils.isBetween(foodSaturation, 0, 5), "Food saturation has to be between 0 and 5");
@@ -1218,7 +1220,7 @@ public class Player extends LivingEntity implements CommandSender {
      *
      * @param resourcePack the resource pack
      */
-    public void setResourcePack(ResourcePack resourcePack) {
+    public void setResourcePack(@NotNull ResourcePack resourcePack) {
         Check.notNull(resourcePack, "The resource pack cannot be null");
         final String url = resourcePack.getUrl();
         final String hash = resourcePack.getHash();
@@ -1367,6 +1369,7 @@ public class Player extends LivingEntity implements CommandSender {
      * This cannot change the displayed level, see {@link #setLevel(int)}.
      *
      * @param exp a percentage between 0 and 1
+     * @throws IllegalArgumentException if {@code exp} is not between 0 and 1
      */
     public void setExp(float exp) {
         Check.argCondition(!MathUtils.isBetween(exp, 0, 1), "Exp should be between 0 and 1");
@@ -1880,6 +1883,7 @@ public class Player extends LivingEntity implements CommandSender {
      * Changes the player permission level.
      *
      * @param permissionLevel the new player permission level
+     * @throws IllegalArgumentException if {@code permissionLevel} is not between 0 and 4
      */
     public void setPermissionLevel(int permissionLevel) {
         Check.argCondition(!MathUtils.isBetween(permissionLevel, 0, 4), "permissionLevel has to be between 0 and 4");

src/main/java/net/minestom/server/network/ConnectionManager.java

@@ -259,6 +259,7 @@ public final class ConnectionManager {
      * Used during disconnection, you shouldn't have to do it manually.
      *
      * @param connection the player connection
+     * @see PlayerConnection#disconnect() to properly disconnect a player
      */
     public void removePlayer(@NotNull PlayerConnection connection) {
         final Player player = this.connectionPlayerMap.get(connection);

src/main/java/net/minestom/server/scoreboard/Sidebar.java

@@ -86,9 +86,12 @@ public class Sidebar implements Scoreboard {
     }
 
     /**
-     * Creates a new {@link ScoreboardLine}
+     * Creates a new {@link ScoreboardLine}.
      *
-     * @param scoreboardLine The new scoreboard line
+     * @param scoreboardLine the new scoreboard line
+     * @throws IllegalStateException    if the sidebar cannot take more line
+     * @throws IllegalArgumentException if the sidebar already contains the line {@code scoreboardLine}
+     *                                  or has a line with the same id
      */
     public void createLine(ScoreboardLine scoreboardLine) {
         synchronized (lines) {
@@ -114,7 +117,7 @@ public class Sidebar implements Scoreboard {
     }
 
     /**
-     * Updates a {@link ScoreboardLine} content through the given identifier
+     * Updates a {@link ScoreboardLine} content through the given identifier.
      *
      * @param id      The identifier of the {@link ScoreboardLine}
      * @param content The new content for the {@link ScoreboardLine}