Fix javadoc warnings.
diff --git a/driver-core/src/main/java/com/datastax/driver/core/NettyOptions.java b/driver-core/src/main/java/com/datastax/driver/core/NettyOptions.java
index 7cfccf5..6f703d9 100644
--- a/driver-core/src/main/java/com/datastax/driver/core/NettyOptions.java
+++ b/driver-core/src/main/java/com/datastax/driver/core/NettyOptions.java
@@ -68,7 +68,6 @@
  * and in particular for OSGi applications, it is likely that such a configuration would lead to
  * compile and/or runtime errors.</strong>
  *
- * @jira_ticket JAVA-640
  * @since 2.0.10
  */
 public class NettyOptions {
@@ -79,7 +78,7 @@
     public static final NettyOptions DEFAULT_INSTANCE = new NettyOptions();
 
     /**
-     * Return the {@link EventLoopGroup} instance to use.
+     * Return the {@code EventLoopGroup} instance to use.
      * <p>
      * This hook is invoked only once at {@link Cluster} initialization;
      * the returned instance will be kept in use throughout the cluster lifecycle.
@@ -89,30 +88,30 @@
      * case implementors should also override {@link #onClusterClose(EventLoopGroup)}
      * to prevent the shared instance to be closed when the cluster is closed.
      * <p>
-     * The default implementation returns a new instance of {@link io.netty.channel.epoll.EpollEventLoopGroup}
+     * The default implementation returns a new instance of {@code io.netty.channel.epoll.EpollEventLoopGroup}
      * if {@link NettyUtil#isEpollAvailable() epoll is available},
-     * or {@link NioEventLoopGroup} otherwise.
+     * or {@code io.netty.channel.nio.NioEventLoopGroup} otherwise.
      *
-     * @param threadFactory The {@link ThreadFactory} to use when creating a new {@link EventLoopGroup} instance;
+     * @param threadFactory The {@link ThreadFactory} to use when creating a new {@code EventLoopGroup} instance;
      *                      The driver will provide its own internal thread factory here.
      *                      It is safe to ignore it and use another thread factory.
-     * @return the {@link EventLoopGroup} instance to use.
+     * @return the {@code EventLoopGroup} instance to use.
      */
     public EventLoopGroup eventLoopGroup(ThreadFactory threadFactory) {
         return NettyUtil.newEventLoopGroupInstance(threadFactory);
     }
 
     /**
-     * Return the specific {@link SocketChannel} subclass to use.
+     * Return the specific {@code SocketChannel} subclass to use.
      * <p>
      * This hook is invoked only once at {@link Cluster} initialization;
      * the returned instance will then be used each time the driver creates a new {@link Connection}
      * and configures a new instance of {@link Bootstrap} for it.
      * <p>
-     * The default implementation returns {@link io.netty.channel.epoll.EpollSocketChannel} if {@link NettyUtil#isEpollAvailable() epoll is available},
-     * or {@link NioSocketChannel} otherwise.
+     * The default implementation returns {@code io.netty.channel.epoll.EpollSocketChannel} if {@link NettyUtil#isEpollAvailable() epoll is available},
+     * or {@code io.netty.channel.socket.nio.NioSocketChannel} otherwise.
      *
-     * @return The {@link SocketChannel} subclass to use.
+     * @return The {@code SocketChannel} subclass to use.
      */
     public Class<? extends SocketChannel> channelClass() {
         return NettyUtil.channelClass();
diff --git a/driver-core/src/main/java/com/datastax/driver/core/PerHostPercentileTracker.java b/driver-core/src/main/java/com/datastax/driver/core/PerHostPercentileTracker.java
index 3f5a22c..c459a9b 100644
--- a/driver-core/src/main/java/com/datastax/driver/core/PerHostPercentileTracker.java
+++ b/driver-core/src/main/java/com/datastax/driver/core/PerHostPercentileTracker.java
@@ -119,12 +119,12 @@
          * resolution and separation. This must be an integer between 0 and 5.
          * <p>
          * If not set explicitly, this value defaults to 3.
+         * <p>
+         * See <a href="http://hdrhistogram.github.io/HdrHistogram/JavaDoc/org/HdrHistogram/Histogram.html">the HdrHistogram Javadocs</a>
+         * for a more detailed explanation on how this parameter affects the resolution of recorded samples.
          *
          * @param numberOfSignificantValueDigits the new value.
          * @return this builder.
-         *
-         * @see <a href="http://hdrhistogram.github.io/HdrHistogram/JavaDoc/org/HdrHistogram/Histogram.html">the HdrHistogram Javadocs</a>
-         * for a more detailed explanation on how this parameter affects the resolution of recorded samples.
          */
         public Builder withNumberOfSignificantValueDigits(int numberOfSignificantValueDigits) {
             this.numberOfSignificantValueDigits = numberOfSignificantValueDigits;
diff --git a/driver-core/src/main/java/com/datastax/driver/core/policies/DefaultRetryPolicy.java b/driver-core/src/main/java/com/datastax/driver/core/policies/DefaultRetryPolicy.java
index 38a9b28..084b299 100644
--- a/driver-core/src/main/java/com/datastax/driver/core/policies/DefaultRetryPolicy.java
+++ b/driver-core/src/main/java/com/datastax/driver/core/policies/DefaultRetryPolicy.java
@@ -110,8 +110,9 @@
      * unavailable exception.
      * <p>
      * This method triggers a retry iff no retry has been executed before
-     * (nbRetry == 0), with {@link RetryDecision#tryNextHost}, otherwise it
-     * throws an exception. The retry will be processed on the next host
+     * (nbRetry == 0), with
+     * {@link RetryPolicy.RetryDecision#tryNextHost(ConsistencyLevel) RetryDecision.tryNextHost(cl)},
+     * otherwise it throws an exception. The retry will be processed on the next host
      * in the query plan according to the current Load Balancing Policy.
      * Where retrying on the same host in the event of an Unavailable exception
      * has almost no chance of success, if the first replica tried happens to