Improve concurrency with help from @evilmidget38

src/main/java/com/massivecraft/factions/Board.java

@@ -78,9 +78,9 @@ public abstract class Board {
      */
     public abstract ArrayList<String> getMap(Faction faction, FLocation flocation, double inDegrees);
 
-    public abstract boolean forceSave();
+    public abstract void forceSave();
 
-    public abstract boolean forceSave(boolean sync);
+    public abstract void forceSave(boolean sync);
 
     public abstract boolean load();
 }

src/main/java/com/massivecraft/factions/zcore/persist/json/JSONBoard.java

@@ -6,7 +6,6 @@ import com.massivecraft.factions.FLocation;
 import com.massivecraft.factions.P;
 import com.massivecraft.factions.zcore.persist.MemoryBoard;
 import com.massivecraft.factions.zcore.util.DiscUtil;
-import org.bukkit.Bukkit;
 
 import java.io.File;
 import java.lang.reflect.Type;
@@ -63,34 +62,12 @@ public class JSONBoard extends MemoryBoard {
         }
     }
 
-    public boolean forceSave() {
+    public void forceSave() {
-        return forceSave(true);
+        forceSave(true);
     }
 
-    public boolean forceSave(boolean sync) {
+    public void forceSave(boolean sync) {
-        if (sync) {
+        DiscUtil.writeCatch(file, P.p.gson.toJson(dumpAsSaveFormat()), sync);
-            try {
-                DiscUtil.write(file, P.p.gson.toJson(dumpAsSaveFormat()));
-            } catch (Exception e) {
-                e.printStackTrace();
-                P.p.log("Failed to save the board to disk.");
-                return false;
-            }
-        } else {
-            Bukkit.getScheduler().runTaskAsynchronously(P.p, new Runnable() {
-                @Override
-                public void run() {
-                    try {
-                        DiscUtil.write(file, P.p.gson.toJson(dumpAsSaveFormat()));
-                    } catch (Exception e) {
-                        e.printStackTrace();
-                        P.p.log("Failed to save the board to disk.");
-                    }
-                }
-            });
-        }
-
-        return true;
     }
 
     public boolean load() {

src/main/java/com/massivecraft/factions/zcore/persist/json/JSONFPlayers.java

@@ -62,20 +62,11 @@ public class JSONFPlayers extends MemoryFPlayers {
             }
         }
 
-        if (sync) {
+        saveCore(file, entitiesThatShouldBeSaved, sync);
-            saveCore(file, entitiesThatShouldBeSaved);
-        } else {
-            Bukkit.getScheduler().runTaskAsynchronously(P.p, new Runnable() {
-                @Override
-                public void run() {
-                    saveCore(file, entitiesThatShouldBeSaved);
-                }
-            });
-        }
     }
 
-    private boolean saveCore(File target, Map<String, JSONFPlayer> data) {
+    private boolean saveCore(File target, Map<String, JSONFPlayer> data, boolean sync) {
-        return DiscUtil.writeCatch(target, this.gson.toJson(data));
+        return DiscUtil.writeCatch(target, this.gson.toJson(data), sync);
     }
 
     public void load() {
@@ -126,7 +117,7 @@ public class JSONFPlayers extends MemoryFPlayers {
             } catch (IOException e) {
                 e.printStackTrace();
             }
-            saveCore(file, (Map<String, JSONFPlayer>) data);
+            saveCore(file, (Map<String, JSONFPlayer>) data, true);
             Bukkit.getLogger().log(Level.INFO, "Backed up your old data at " + file.getAbsolutePath());
 
             // Start fetching those UUIDs
@@ -170,7 +161,7 @@ public class JSONFPlayers extends MemoryFPlayers {
                 Bukkit.getLogger().log(Level.INFO, "While converting we found names that either don't have a UUID or aren't players and removed them from storage.");
                 Bukkit.getLogger().log(Level.INFO, "The following names were detected as being invalid: " + StringUtils.join(invalidList, ", "));
             }
-            saveCore(this.file, (Map<String, JSONFPlayer>) data); // Update the
+            saveCore(this.file, (Map<String, JSONFPlayer>) data, true); // Update the
             // flatfile
             Bukkit.getLogger().log(Level.INFO, "Done converting players.json to UUID.");
         }

src/main/java/com/massivecraft/factions/zcore/persist/json/JSONFactions.java

@@ -62,20 +62,11 @@ public class JSONFactions extends MemoryFactions {
             entitiesThatShouldBeSaved.put(entity.getId(), (JSONFaction) entity);
         }
 
-        if (sync) {
+        saveCore(file, entitiesThatShouldBeSaved, sync);
-            saveCore(file, entitiesThatShouldBeSaved);
-        } else {
-            Bukkit.getScheduler().runTaskAsynchronously(P.p, new Runnable() {
-                @Override
-                public void run() {
-                    saveCore(file, entitiesThatShouldBeSaved);
-                }
-            });
-        }
     }
 
-    private boolean saveCore(File target, Map<String, JSONFaction> entities) {
+    private boolean saveCore(File target, Map<String, JSONFaction> entities, boolean sync) {
-        return DiscUtil.writeCatch(target, this.gson.toJson(entities));
+        return DiscUtil.writeCatch(target, this.gson.toJson(entities), sync);
     }
 
     public void load() {
@@ -129,7 +120,7 @@ public class JSONFactions extends MemoryFactions {
             } catch (IOException e) {
                 e.printStackTrace();
             }
-            saveCore(file, (Map<String, JSONFaction>) data);
+            saveCore(file, (Map<String, JSONFaction>) data, true);
             Bukkit.getLogger().log(Level.INFO, "Backed up your old data at " + file.getAbsolutePath());
 
             Bukkit.getLogger().log(Level.INFO, "Please wait while Factions converts " + needsUpdate + " old player names to UUID. This may take a while.");
@@ -189,7 +180,7 @@ public class JSONFactions extends MemoryFactions {
                 }
             }
 
-            saveCore(this.file, (Map<String, JSONFaction>) data); // Update the flatfile
+            saveCore(this.file, (Map<String, JSONFaction>) data, true); // Update the flatfile
             Bukkit.getLogger().log(Level.INFO, "Done converting factions.json to UUID.");
         }
         return data;

src/main/java/com/massivecraft/factions/zcore/util/DiscUtil.java

@@ -1,6 +1,13 @@
 package com.massivecraft.factions.zcore.util;
 
+import com.massivecraft.factions.P;
+import org.bukkit.Bukkit;
+
 import java.io.*;
+import java.util.HashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
 
 public class DiscUtil {
 
@@ -14,6 +21,7 @@ public class DiscUtil {
     // BYTE
     // -------------------------------------------- //
 
+
     public static byte[] readBytes(File file) throws IOException {
         int length = (int) file.length();
         byte[] output = new byte[length];
@@ -48,13 +56,52 @@ public class DiscUtil {
     // CATCH
     // -------------------------------------------- //
 
-    public static boolean writeCatch(File file, String content) {
+    private static HashMap<String, Lock> locks = new HashMap<String, Lock>();
-        try {
+
-            write(file, content);
+    public static boolean writeCatch(final File file, final String content, boolean sync) {
-            return true;
+        final byte[] bytes = utf8(content);
-        } catch (Exception e) {
+        String name = file.getName();
-            return false;
+        final Lock lock;
+
+        // Create lock for each file if there isn't already one.
+        if (locks.containsKey(name)) {
+            lock = locks.get(name);
+        } else {
+            ReadWriteLock rwl = new ReentrantReadWriteLock();
+            lock = rwl.writeLock();
+            locks.put(name, lock);
         }
+
+        if (sync) {
+            lock.lock();
+            try {
+                FileOutputStream out = new FileOutputStream(file);
+                out.write(bytes);
+                out.close();
+            } catch (IOException e) {
+                e.printStackTrace();
+            } finally {
+                lock.unlock();
+            }
+        } else {
+            Bukkit.getScheduler().runTaskAsynchronously(P.p, new Runnable() {
+                @Override
+                public void run() {
+                    lock.lock();
+                    try {
+                        FileOutputStream out = new FileOutputStream(file);
+                        out.write(bytes);
+                        out.close();
+                    } catch (IOException e) {
+                        e.printStackTrace();
+                    } finally {
+                        lock.unlock();
+                    }
+                }
+            });
+        }
+
+        return true; // don't really care but for some reason this is a boolean.
     }
 
     public static String readCatch(File file) {

src/main/java/com/massivecraft/factions/zcore/util/Persist.java

@@ -100,7 +100,7 @@ public class Persist {
     }
 
     public boolean save(Object instance, File file) {
-        return DiscUtil.writeCatch(file, p.gson.toJson(instance));
+        return DiscUtil.writeCatch(file, p.gson.toJson(instance), true);
     }
 
     // LOAD BY CLASS