SPVBlockStore: Remove mmap hack for Windows (blocking maven releases)

core/src/main/java/org/bitcoinj/store/SPVBlockStore.java

@@ -278,10 +278,6 @@ public class SPVBlockStore implements BlockStore {
     public void close() throws BlockStoreException {
         try {
             buffer.force();
-            if (System.getProperty("os.name").toLowerCase().contains("win")) {
-                log.info("Windows mmap hack: Forcing buffer cleaning");
-                WindowsMMapHack.forceRelease(buffer);
-            }
             buffer = null;  // Allow it to be GCd and the underlying file mapping to go away.
             randomAccessFile.close();
         } catch (IOException e) {

core/src/main/java/org/bitcoinj/store/WindowsMMapHack.java

-/*
- * Copyright by the original author or authors.
- * 
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.bitcoinj.store;
-
-import sun.misc.*;
-import sun.nio.ch.*;
-
-import java.nio.*;
-
-/**
- * <p>This class knows how to force an mmap'd ByteBuffer to reliquish its file handles before it becomes garbage collected,
- * by exploiting implementation details of the HotSpot JVM implementation.</p>
- *
- * <p>This is required on Windows because otherwise an attempt to delete a file that is still mmapped will fail. This can
- * happen when a user requests a "restore from seed" function, which involves deleting and recreating the chain file.
- * At some point we should stop using mmap in SPVBlockStore and we can then delete this class.</p>
- *
- * <p>It is a separate class to avoid hitting unknown imports when running on other JVMs.</p>
- */
-public class WindowsMMapHack {
-    public static void forceRelease(MappedByteBuffer buffer) {
-        Cleaner cleaner = ((DirectBuffer) buffer).cleaner();
-        if (cleaner != null) cleaner.clean();
-    }
-}