diff --git a/common/src/main/java/com/lishid/openinv/util/Cache.java b/common/src/main/java/com/lishid/openinv/util/Cache.java
index f6dce83..dc627cc 100644
--- a/common/src/main/java/com/lishid/openinv/util/Cache.java
+++ b/common/src/main/java/com/lishid/openinv/util/Cache.java
@@ -19,11 +19,12 @@ package com.lishid.openinv.util;
 import com.google.common.collect.Multimap;
 import com.google.common.collect.TreeMultimap;
 import java.util.ArrayList;
-import java.util.Comparator;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
+import java.util.function.Function;
 
 /**
  * A minimal thread-safe time-based cache implementation backed by a HashMap and TreeMultimap.
@@ -35,7 +36,7 @@ public class Cache<K, V> {
     private final Map<K, V> internal;
     private final Multimap<Long, K> expiry;
     private final long retention;
-    private final Function<V> inUseCheck, postRemoval;
+    private final Function<V, Boolean> inUseCheck, postRemoval;
 
     /**
      * Constructs a Cache with the specified retention duration, in use function, and post-removal function.
@@ -44,21 +45,10 @@ public class Cache<K, V> {
      * @param inUseCheck Function used to check if a key is considered in use
      * @param postRemoval Function used to perform any operations required when a key is invalidated
      */
-    public Cache(final long retention, final Function<V> inUseCheck, final Function<V> postRemoval) {
-        this.internal = new HashMap<K, V>();
+    public Cache(final long retention, final Function<V, Boolean> inUseCheck, final Function<V, Boolean> postRemoval) {
+        this.internal = new HashMap<>();
 
-        this.expiry = TreeMultimap.create(new Comparator<Long>() {
-                    @Override
-                    public int compare(final Long long1, final Long long2) {
-                        return long1.compareTo(long2);
-                    }
-                },
-                new Comparator<K>() {
-                    @Override
-                    public int compare(final K k1, final K k2) {
-                        return k1 == k2 || k1 != null && k1.equals(k2) ? 0 : 1;
-                    }
-                });
+        this.expiry = TreeMultimap.create(Long::compareTo, (k1, k2) -> Objects.equals(k1, k2) ? 0 : 1);
 
         this.retention = retention;
         this.inUseCheck = inUseCheck;
@@ -146,7 +136,7 @@ public class Cache<K, V> {
     public void invalidateAll() {
         synchronized (this.internal) {
             for (V value : this.internal.values()) {
-                this.postRemoval.run(value);
+                this.postRemoval.apply(value);
             }
             this.expiry.clear();
             this.internal.clear();
@@ -160,7 +150,7 @@ public class Cache<K, V> {
     private void lazyCheck() {
         long now = System.currentTimeMillis();
         synchronized (this.internal) {
-            List<K> inUse = new ArrayList<K>();
+            List<K> inUse = new ArrayList<>();
             for (Iterator<Map.Entry<Long, K>> iterator = this.expiry.entries().iterator(); iterator
                     .hasNext();) {
                 Map.Entry<Long, K> entry = iterator.next();
@@ -171,7 +161,7 @@ public class Cache<K, V> {
 
                 iterator.remove();
 
-                if (this.inUseCheck.run(this.internal.get(entry.getValue()))) {
+                if (this.inUseCheck.apply(this.internal.get(entry.getValue()))) {
                     inUse.add(entry.getValue());
                     continue;
                 }
@@ -182,7 +172,7 @@ public class Cache<K, V> {
                     continue;
                 }
 
-                this.postRemoval.run(value);
+                this.postRemoval.apply(value);
             }
 
             long nextExpiry = now + this.retention;
diff --git a/common/src/main/java/com/lishid/openinv/util/Function.java b/common/src/main/java/com/lishid/openinv/util/Function.java
deleted file mode 100644
index b650684..0000000
--- a/common/src/main/java/com/lishid/openinv/util/Function.java
+++ /dev/null
@@ -1,28 +0,0 @@
-/*
- * Copyright (C) 2011-2020 lishid. All rights reserved.
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, version 3.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program. If not, see <http://www.gnu.org/licenses/>.
- */
-
-package com.lishid.openinv.util;
-
-/**
- * Abstraction for some simple cache calls.
- *
- * @author Jikoo
- */
-public abstract class Function<V> {
-
-    public abstract boolean run(V value);
-
-}
diff --git a/plugin/src/main/java/com/lishid/openinv/OpenInv.java b/plugin/src/main/java/com/lishid/openinv/OpenInv.java
index bc49b5c..9553332 100644
--- a/plugin/src/main/java/com/lishid/openinv/OpenInv.java
+++ b/plugin/src/main/java/com/lishid/openinv/OpenInv.java
@@ -70,47 +70,41 @@ public class OpenInv extends JavaPlugin implements IOpenInv {
     private final Multimap<String, Class<? extends Plugin>> pluginUsage = HashMultimap.create();
 
     private final Cache<String, Player> playerCache = new Cache<>(300000L,
-            new Function<Player>() {
-                @Override
-                public boolean run(final Player value) {
+            value -> {
+                String key = OpenInv.this.getPlayerID(value);
 
-                    String key = OpenInv.this.getPlayerID(value);
-                    return OpenInv.this.inventories.containsKey(key)
-                            && OpenInv.this.inventories.get(key).isInUse()
-                            || OpenInv.this.enderChests.containsKey(key)
-                            && OpenInv.this.enderChests.get(key).isInUse()
-                            || OpenInv.this.pluginUsage.containsKey(key);
+                return OpenInv.this.inventories.containsKey(key)
+                        && OpenInv.this.inventories.get(key).isInUse()
+                        || OpenInv.this.enderChests.containsKey(key)
+                        && OpenInv.this.enderChests.get(key).isInUse()
+                        || OpenInv.this.pluginUsage.containsKey(key);
+            },
+            value -> {
+                String key = OpenInv.this.getPlayerID(value);
+
+                // Check if inventory is stored, and if it is, remove it and eject all viewers
+                if (OpenInv.this.inventories.containsKey(key)) {
+                    Inventory inv = OpenInv.this.inventories.remove(key).getBukkitInventory();
+                    List<HumanEntity> viewers = inv.getViewers();
+                    for (HumanEntity entity : viewers.toArray(new HumanEntity[0])) {
+                        entity.closeInventory();
+                    }
                 }
-            }, new Function<Player>() {
-        @Override
-        public boolean run(final Player value) {
 
-            String key = OpenInv.this.getPlayerID(value);
-
-            // Check if inventory is stored, and if it is, remove it and eject all viewers
-            if (OpenInv.this.inventories.containsKey(key)) {
-                Inventory inv = OpenInv.this.inventories.remove(key).getBukkitInventory();
-                List<HumanEntity> viewers = inv.getViewers();
-                for (HumanEntity entity : viewers.toArray(new HumanEntity[0])) {
-                    entity.closeInventory();
+                // Check if ender chest is stored, and if it is, remove it and eject all viewers
+                if (OpenInv.this.enderChests.containsKey(key)) {
+                    Inventory inv = OpenInv.this.enderChests.remove(key).getBukkitInventory();
+                    List<HumanEntity> viewers = inv.getViewers();
+                    for (HumanEntity entity : viewers.toArray(new HumanEntity[0])) {
+                        entity.closeInventory();
+                    }
                 }
-            }
 
-            // Check if ender chest is stored, and if it is, remove it and eject all viewers
-            if (OpenInv.this.enderChests.containsKey(key)) {
-                Inventory inv = OpenInv.this.enderChests.remove(key).getBukkitInventory();
-                List<HumanEntity> viewers = inv.getViewers();
-                for (HumanEntity entity : viewers.toArray(new HumanEntity[0])) {
-                    entity.closeInventory();
+                if (!OpenInv.this.disableSaving() && !value.isOnline()) {
+                    value.saveData();
                 }
-            }
-
-            if (!OpenInv.this.disableSaving() && !value.isOnline()) {
-                value.saveData();
-            }
-            return true;
-        }
-    });
+                return true;
+            });
 
     private InternalAccessor accessor;
 
diff --git a/pom.xml b/pom.xml
index e107501..959b6c3 100644
--- a/pom.xml
+++ b/pom.xml
@@ -89,7 +89,7 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-shade-plugin</artifactId>
-        <version>3.0.0</version>
+        <version>3.2.2</version>
         <configuration>
           <filters>
             <filter>