--- a/net/minecraft/Util.java
+++ b/net/minecraft/Util.java
@@ -95,6 +95,22 @@
     private static final TracingExecutor BACKGROUND_EXECUTOR = makeExecutor("Main");
     private static final TracingExecutor IO_POOL = makeIoExecutor("IO-Worker-", false);
     private static final TracingExecutor DOWNLOAD_POOL = makeIoExecutor("Download-", true);
+    // Paper start - don't submit BLOCKING PROFILE LOOKUPS to the world gen thread
+    public static final ExecutorService PROFILE_EXECUTOR = Executors.newFixedThreadPool(2, new java.util.concurrent.ThreadFactory() {
+
+        private final AtomicInteger count = new AtomicInteger();
+
+        @Override
+        public Thread newThread(Runnable run) {
+            Thread ret = new Thread(run);
+            ret.setName("Profile Lookup Executor #" + this.count.getAndIncrement());
+            ret.setUncaughtExceptionHandler((Thread thread, Throwable throwable) -> {
+                LOGGER.error("Uncaught exception in thread " + thread.getName(), throwable);
+            });
+            return ret;
+        }
+    });
+    // Paper end - don't submit BLOCKING PROFILE LOOKUPS to the world gen thread
     private static final DateTimeFormatter FILENAME_DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd_HH.mm.ss", Locale.ROOT);
     public static final int LINEAR_LOOKUP_THRESHOLD = 8;
     private static final Set<String> ALLOWED_UNTRUSTED_LINK_PROTOCOLS = Set.of("http", "https");
@@ -136,7 +152,7 @@
     }
 
     public static long getNanos() {
-        return timeSource.getAsLong();
+        return System.nanoTime(); // Paper
     }
 
     public static long getEpochMillis() {
@@ -537,7 +553,7 @@
     public static <K extends Enum<K>, V> EnumMap<K, V> makeEnumMap(Class<K> enumClass, Function<K, V> mapper) {
         EnumMap<K, V> enumMap = new EnumMap<>(enumClass);
 
-        for (K enum_ : (Enum[])enumClass.getEnumConstants()) {
+        for (K enum_ : enumClass.getEnumConstants()) { // Paper - decompile error
             enumMap.put(enum_, mapper.apply(enum_));
         }