Update SyncUtil for JDK11 and JDK17

Remove --add-opens java.base/java.nio=ALL-UNNAMED which is not needed anymore

patch by Ekaterina Dimitrova; reviewed by Jacek Lewandowki for CASSANDRA-17909

build.xml

@@ -259,7 +259,6 @@
 
         <string>--add-opens java.base/sun.nio.ch=ALL-UNNAMED</string>
         <string>--add-opens java.base/java.io=ALL-UNNAMED</string>
-        <string>--add-opens java.base/java.nio=ALL-UNNAMED</string>
         <string>--add-opens java.base/java.util.concurrent=ALL-UNNAMED</string>
         <string>--add-opens java.base/java.util=ALL-UNNAMED</string>
         <string>--add-opens java.base/java.util.concurrent.atomic=ALL-UNNAMED</string>

conf/jvm17-clients.options

@@ -51,7 +51,6 @@
 # to be addressed in CASSANDRA-17850
 --add-opens java.base/sun.nio.ch=ALL-UNNAMED
 --add-opens java.base/java.io=ALL-UNNAMED
---add-opens java.base/java.nio=ALL-UNNAMED
 # to be addressed during jamm maintenance
 --add-opens java.base/java.util.concurrent=ALL-UNNAMED
 --add-opens java.base/java.util=ALL-UNNAMED

conf/jvm17-server.options

@@ -90,7 +90,6 @@
 --add-opens java.base/sun.nio.ch=ALL-UNNAMED
 # https://chronicle.software/chronicle-support-java-17/
 --add-opens java.base/java.io=ALL-UNNAMED
---add-opens java.base/java.nio=ALL-UNNAMED
 #to be addressed during jamm maintenance
 --add-opens java.base/java.util.concurrent=ALL-UNNAMED
 --add-opens java.base/java.util=ALL-UNNAMED

src/java/org/apache/cassandra/utils/SyncUtil.java

@@ -21,11 +21,9 @@
 package org.apache.cassandra.utils;
 
 import java.io.*;
-import java.lang.reflect.Field;
 import java.nio.MappedByteBuffer;
 import java.nio.channels.ClosedChannelException;
 import java.nio.channels.FileChannel;
-import java.util.concurrent.atomic.AtomicInteger;
 
 import com.google.common.base.Preconditions;
 
@@ -38,57 +36,17 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /*
- * A wrapper around various mechanisms for syncing files that makes it possible it intercept
+ * A wrapper around various mechanisms for syncing files that makes it possible to intercept
  * and skip syncing. Useful for unit tests in certain environments where syncs can have outliers
- * bad enough to causes tests to run 10s of seconds longer.
+ * bad enough to cause tests to run 10s of seconds longer.
  */
 public class SyncUtil
 {
     public static final boolean SKIP_SYNC;
-
-    private static final Field mbbFDField;
-    private static final Field fdClosedField;
-    private static final Field fdUseCountField;
-
     private static final Logger logger = LoggerFactory.getLogger(SyncUtil.class);
 
     static
     {
-        Field mbbFDFieldTemp = null;
-        try
-        {
-            mbbFDFieldTemp = MappedByteBuffer.class.getDeclaredField("fd");
-            mbbFDFieldTemp.setAccessible(true);
-        }
-        catch (NoSuchFieldException e)
-        {
-        }
-        mbbFDField = mbbFDFieldTemp;
-
-        //Java 8
-        Field fdClosedFieldTemp = null;
-        try
-        {
-            fdClosedFieldTemp = FileDescriptor.class.getDeclaredField("closed");
-            fdClosedFieldTemp.setAccessible(true);
-        }
-        catch (NoSuchFieldException e)
-        {
-        }
-        fdClosedField = fdClosedFieldTemp;
-
-        //Java 7
-        Field fdUseCountTemp = null;
-        try
-        {
-            fdUseCountTemp = FileDescriptor.class.getDeclaredField("useCount");
-            fdUseCountTemp.setAccessible(true);
-        }
-        catch (NoSuchFieldException e)
-        {
-        }
-        fdUseCountField = fdUseCountTemp;
-
         //If skipping syncing is requested by any means then skip them.
         boolean skipSyncProperty = CassandraRelevantProperties.TEST_CASSANDRA_SKIP_SYNC.getBoolean();
         boolean skipSyncEnv = CassandraRelevantEnv.CASSANDRA_SKIP_SYNC.getBoolean();
@@ -110,21 +68,6 @@ public class SyncUtil
         }
         if (SKIP_SYNC)
         {
-            Object fd = null;
-            try
-            {
-                if (mbbFDField != null)
-                {
-                    fd = mbbFDField.get(buf);
-                }
-            }
-            catch (Exception e)
-            {
-                throw new RuntimeException(e);
-            }
-            //This is what MappedByteBuffer.force() throws if a you call force() on an umapped buffer
-            if (mbbFDField != null && fd == null)
-                throw new UnsupportedOperationException();
             return buf;
         }
         else
@@ -132,40 +75,12 @@ public class SyncUtil
             return buf.force();
         }
     }
-
+    
     public static void sync(FileDescriptor fd) throws SyncFailedException
     {
         Preconditions.checkNotNull(fd);
-        if (SKIP_SYNC)
+        if (!SKIP_SYNC)
-        {
-            boolean closed = false;
-            try
-            {
-                if (fdClosedField != null)
-                    closed = fdClosedField.getBoolean(fd);
-            }
-            catch (Exception e)
-            {
-                throw new RuntimeException(e);
-            }
-
-            int useCount = 1;
-            try
-            {
-                if (fdUseCountField != null)
-                    useCount = ((AtomicInteger)fdUseCountField.get(fd)).get();
-            }
-            catch (Exception e)
-            {
-                throw new RuntimeException(e);
-            }
-            if (closed || !fd.valid() || useCount < 0)
-                throw new SyncFailedException("Closed " + closed + " valid " + fd.valid() + " useCount " + useCount);
-        }
-        else
-        {
             fd.sync();
-        }
     }
 
     public static void force(FileChannel fc, boolean metaData) throws IOException
@@ -192,8 +107,8 @@ public class SyncUtil
     {
         if (SKIP_SYNC)
             return;
-        else
+
-            NativeLibrary.trySync(fd);
+        NativeLibrary.trySync(fd);
     }
 
     public static void trySyncDir(File dir)