Changed access modifiers (or whatever they're called)

src/main/java/DataLock.java

@@ -5,11 +5,11 @@ import org.bukkit.scheduler.BukkitRunnable;
 import java.util.HashSet;
 import java.util.UUID;
 
-public class DataLock implements DataLockInterface {
+class DataLock implements DataLockInterface {
 
     private static DataLock instance = null;
 
-    public static DataLock getInstance() {
+    protected static DataLock getInstance() {
         if (instance == null)
             instance = new DataLock();
         return instance;
@@ -35,7 +35,7 @@ public class DataLock implements DataLockInterface {
 
     private final HashSet<String> activeChannels = new HashSet<>();
 
-    public boolean removeActiveRequest(RequestType requestType, IdempotencyData idempotencyData) {
+    protected boolean removeActiveRequest(RequestType requestType, IdempotencyData idempotencyData) {
         return activeRequests.removeIdempotencyData(requestType, idempotencyData);
     }
 

src/main/java/DataLockLib.java

@@ -2,7 +2,7 @@ import org.bukkit.plugin.java.JavaPlugin;
 
 public class DataLockLib extends JavaPlugin {
 
-    public static DataLockLib instance;
+    private static DataLockLib instance;
 
     protected static DataLockLib getInstance() {
         return instance;

src/main/java/Idempotency.java

@@ -3,11 +3,11 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Set;
 
-public class Idempotency {
+class Idempotency {
 
     private final HashMap<RequestType, HashSet<IdempotencyData>> idempotencyMap;
 
-    public Idempotency() {
+    protected Idempotency() {
         idempotencyMap = new HashMap<>();
     }
 
@@ -24,7 +24,7 @@ public class Idempotency {
      * @param idempotencyData Data to add to the set
      * @return true if entry did not exist yet
      */
-    public synchronized boolean putIdempotencyData(RequestType requestType, IdempotencyData idempotencyData) {
+    protected synchronized boolean putIdempotencyData(RequestType requestType, IdempotencyData idempotencyData) {
         HashSet<IdempotencyData> idempotencySet = getIdempotencySet(requestType);
         boolean result = idempotencySet.add(idempotencyData);
         putIdempotencySet(requestType, idempotencySet);
@@ -36,14 +36,14 @@ public class Idempotency {
      * @param idempotencyData Data to remove from the set
      * @return True if the data that was requested to be removed was in the set and was removed
      */
-    public synchronized boolean removeIdempotencyData(RequestType requestType, IdempotencyData idempotencyData) {
+    protected synchronized boolean removeIdempotencyData(RequestType requestType, IdempotencyData idempotencyData) {
         HashSet<IdempotencyData> idempotencySet = getIdempotencySet(requestType);
         boolean result = idempotencySet.remove(idempotencyData);
         putIdempotencySet(requestType, idempotencySet);
         return result;
     }
 
-    public synchronized Set<IdempotencyData> getIdempotencyData(RequestType requestType) {
+    protected synchronized Set<IdempotencyData> getIdempotencyData(RequestType requestType) {
         return Collections.unmodifiableSet(getIdempotencySet(requestType));
     }
 }

src/main/java/LockResponseEvent.java

@@ -22,10 +22,18 @@ public class LockResponseEvent extends Event {
         return channel;
     }
 
+    public ResponseType getResponseType() {
+        return responseType;
+    }
+
     public String getData() {
         return data;
     }
 
+    public boolean getResult() {
+        return result;
+    }
+
     public @NotNull HandlerList getHandlers() {
         return handlers;
     }

src/main/java/PluginMessageListener.java

@@ -6,7 +6,7 @@ import org.jetbrains.annotations.NotNull;
 
 import java.util.UUID;
 
-public class PluginMessageListener implements org.bukkit.plugin.messaging.PluginMessageListener {
+class PluginMessageListener implements org.bukkit.plugin.messaging.PluginMessageListener {
 
     private final DataLock dataLock;
     private final Idempotency alreadyReceived;

src/main/java/RequestType.java

@@ -1,4 +1,4 @@
-public enum RequestType {
+enum RequestType {
     TRY_LOCK("try-lock"),
     TRY_UNLOCK("try-unlock"),
     CHECK_LOCK("check-lock");