Make end tag singleton

worldedit-bukkit/src/main/java/com/boydti/fawe/bukkit/adapter/Spigot_v1_13_R1.java

@@ -399,7 +399,7 @@ public final class Spigot_v1_13_R1 implements BukkitImplAdapter<NBTBase> {
         } else if (foreign instanceof NBTTagString) {
             return new StringTag(foreign.b_()); // data
         } else if (foreign instanceof NBTTagEnd) {
-            return new EndTag();
+            return EndTag.INSTANCE;
         } else {
             throw new IllegalArgumentException("Don't know how to make native " + foreign.getClass().getCanonicalName());
         }

worldedit-core/src/main/java/com/boydti/fawe/FaweCache.java

@@ -174,7 +174,7 @@ public class FaweCache {
             if (clazz.getName().startsWith("com.intellectualcrafters.jnbt")) {
                 try {
                     if (clazz.getName().equals("com.intellectualcrafters.jnbt.EndTag")) {
-                        return new EndTag();
+                        return EndTag.INSTANCE;
                     }
                     Field field = clazz.getDeclaredField("value");
                     field.setAccessible(true);

worldedit-core/src/main/java/com/boydti/fawe/jnbt/NBTStreamer.java

@@ -6,18 +6,24 @@ import com.boydti.fawe.object.exception.FaweException;
 import com.sk89q.jnbt.NBTInputStream;
 import java.io.IOException;
 import java.util.HashMap;
+import java.util.Map;
 import java.util.function.BiConsumer;
 import java.util.function.Function;
 
 public class NBTStreamer {
     private final NBTInputStream is;
-    private final HashMap<String, BiConsumer> readers;
+    private final Map<String, BiConsumer> readers;
 
     public NBTStreamer(NBTInputStream stream) {
         this.is = stream;
         readers = new HashMap<>();
     }
 
+    public NBTStreamer(NBTInputStream stream, Map<String, BiConsumer> readers) {
+        this.is = stream;
+        this.readers = readers;
+    }
+
     /**
      * Reads the entire stream and runs the applicable readers
      *

worldedit-core/src/main/java/com/sk89q/jnbt/EndTag.java

@@ -23,6 +23,9 @@ package com.sk89q.jnbt;
  * The {@code TAG_End} tag.
  */
 public final class EndTag extends Tag {
+    public static final EndTag INSTANCE = new EndTag();
+
+    private EndTag() {}
 
     @Override
     public Object getValue() {

worldedit-core/src/main/java/com/sk89q/jnbt/NBTInputStream.java

@@ -526,7 +526,7 @@ public final class NBTInputStream implements Closeable {
                     throw new IOException(
                             "TAG_End found without a TAG_Compound/TAG_List tag preceding it.");
                 } else {
-                    return new EndTag();
+                    return EndTag.INSTANCE;
                 }
             case NBTConstants.TYPE_BYTE:
                 return new ByteTag(is.readByte());

worldedit-forge/src/main/java/com/sk89q/worldedit/forge/NBTConverter.java

@@ -217,7 +217,7 @@ final class NBTConverter {
     }
 
     public static EndTag fromNative(NBTTagEnd other) {
-        return new EndTag();
+        return EndTag.INSTANCE;
     }
 
     public static LongTag fromNative(NBTTagLong other) {