Java 1.5 compat.

src/main/java/org/bukkit/craftbukkit/util/Java15Compat.java

@@ -0,0 +1,34 @@
+package org.bukkit.craftbukkit.util;
+
+import java.lang.reflect.Array;
+
+public class Java15Compat {
+    public static <T> T[] Arrays_copyOf(T[] original, int newLength) {
+        if (0 <= newLength) {
+            return org.bukkit.util.Java15Compat.Arrays_copyOfRange(original, 0, newLength);
+        }
+        throw new NegativeArraySizeException();
+    }
+
+    public static long[] Arrays_copyOf(long[] original, int newLength) {
+        if (0 <= newLength) {
+            return Arrays_copyOfRange(original, 0, newLength);
+        }
+        throw new NegativeArraySizeException();
+    }
+
+    private static long[] Arrays_copyOfRange(long[] original, int start, int end) {
+        if (original.length >= start && 0 <= start) {
+            if (start <= end) {
+                int length = end - start;
+                int copyLength = Math.min( length, original.length - start);
+                long[] copy = (long[]) Array.newInstance(original.getClass().getComponentType(), length);
+                System.arraycopy(original, start, copy, 0, copyLength);
+                return copy;
+            }
+            throw new IllegalArgumentException();
+        }
+        throw new ArrayIndexOutOfBoundsException();
+    }
+
+}

src/main/java/org/bukkit/craftbukkit/util/LongHashset.java

@@ -1,5 +1,5 @@
 package org.bukkit.craftbukkit.util;
-import java.util.Arrays;
+import static org.bukkit.craftbukkit.util.Java15Compat.Arrays_copyOf;
 
 public class LongHashset extends LongHash {
     long values[][][] = new long[256][][];
@@ -31,7 +31,7 @@ public class LongHashset extends LongHash {
                     return;
                 }
             }
-            outer[outerIdx] = inner = Arrays.copyOf(inner, i+1);
+            outer[outerIdx] = inner = Arrays_copyOf(inner, i+1);
             inner[i] = key;
             count++;
         }
@@ -66,7 +66,7 @@ public class LongHashset extends LongHash {
                 if(i != max) {
                     inner[i] = inner[max];
                 }
-                outer[(int) ((key >> 32) & 255)] = (max == 0 ? null : Arrays.copyOf(inner, max));
+                outer[(int) ((key >> 32) & 255)] = (max == 0 ? null : Arrays_copyOf(inner, max));
                 return;
             }
         }
@@ -80,7 +80,7 @@ public class LongHashset extends LongHash {
                 if(inner == null || inner.length == 0) continue;
                 count--;
                 long ret = inner[inner.length - 1];
-                outer[i] = Arrays.copyOf(inner, inner.length - 1);
+                outer[i] = Arrays_copyOf(inner, inner.length - 1);
                 return ret;
                 
             }

src/main/java/org/bukkit/craftbukkit/util/LongHashtable.java

@@ -4,6 +4,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import net.minecraft.server.Chunk;
 import net.minecraft.server.MinecraftServer;
+import static org.bukkit.craftbukkit.util.Java15Compat.Arrays_copyOf;
 
 public class LongHashtable<V> extends LongHash
 {
@@ -55,7 +56,7 @@ public class LongHashtable<V> extends LongHash
                     return;
                 }
             }
-            outer[outerIdx] = inner = Arrays.copyOf(inner, i + i);
+            outer[outerIdx] = inner = Arrays_copyOf(inner, i + i);
             inner[i] = new Entry(key, value);
         }
     }