Polishing.

Tweak wording around thread-safety. Include notices in connection factories.

Reformat asciidoc.

See #2653
Original pull request: #2667

src/main/java/org/springframework/data/redis/connection/RedisClusterConnection.java

@@ -28,6 +28,9 @@ import org.springframework.util.Assert;
  * {@link RedisClusterNode} can be obtained from {@link #clusterGetNodes()} or it can be constructed using either
  * {@link RedisClusterNode#getHost() host} and {@link RedisClusterNode#getPort()} or the {@link RedisClusterNode#getId()
  * node Id}.
+ * <p>
+ * {@link RedisClusterConnection Redis connections}, unlike perhaps their underlying native connection are not
+ * Thread-safe and should not be shared across multiple threads.
  *
  * @author Christoph Strobl
  * @author Mark Paluch

src/main/java/org/springframework/data/redis/connection/RedisConnection.java

@@ -22,15 +22,14 @@ import org.springframework.dao.DataAccessException;
 /**
  * A connection to a Redis server.
  * <p>
- * The {@link RedisConnection} interface serves as a common abstraction across various Redis client libraries
- * (or drivers).
+ * The {@link RedisConnection} interface serves as a common abstraction across various Redis client libraries (or
+ * drivers).
  * <p>
  * Additionally, performs exception translation between the underlying Redis client library and Spring DAO exceptions.
  * The methods follow as much as possible the Redis names and conventions.
  * <p>
- * Spring Data Redis {@link RedisConnection connections}, unlike perhaps their underlying native connection (for example:
- * the Lettuce {@literal StatefulRedisConnection}) are not Thread-safe. Please refer to the corresponding the Javadoc
- * for Redis client library (driver) specific connections provided by Spring Data Redis for more details.
+ * {@link RedisConnection Redis connections}, unlike perhaps their underlying native connection are not Thread-safe and
+ * should not be shared across multiple threads.
  *
  * @author Costin Leau
  * @author Christoph Strobl

src/main/java/org/springframework/data/redis/connection/jedis/JedisClusterConnection.java

@@ -35,7 +35,6 @@ import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.beans.DirectFieldAccessor;
 import org.springframework.beans.PropertyAccessor;
 import org.springframework.dao.DataAccessException;
@@ -61,6 +60,8 @@ import org.springframework.util.Assert;
  * {@link RedisClusterConnection} implementation on top of {@link JedisCluster}.<br/>
  * Uses the native {@link JedisCluster} api where possible and falls back to direct node communication using
  * {@link Jedis} where needed.
+ * <p>
+ * This class is not Thread-safe and instances should not be shared across threads.
  *
  * @author Christoph Strobl
  * @author Mark Paluch

src/main/java/org/springframework/data/redis/connection/jedis/JedisConnection.java

@@ -41,7 +41,6 @@ import java.util.function.Supplier;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
@@ -60,10 +59,7 @@ import org.springframework.util.CollectionUtils;
 /**
  * {@code RedisConnection} implementation on top of <a href="https://github.com/redis/jedis">Jedis</a> library.
  * <p>
- * WARNING: The {@link JedisConnection} class is not Thread-safe. This class requires and uses a
- * {@literal Jedis} instance from the Jedis client library (driver), which is very clearly
- * <a href="https://github.com/redis/jedis/wiki/Getting-started#using-jedis-in-a-multithreaded-environment">documented</a>
- * as not Thread-safe.
+ * This class is not Thread-safe and instances should not be shared across threads.
  *
  * @author Costin Leau
  * @author Jennifer Hickey

src/main/java/org/springframework/data/redis/connection/jedis/JedisConnectionFactory.java

@@ -79,6 +79,11 @@ import org.springframework.util.ObjectUtils;
  * connection. {@link #afterPropertiesSet() Initialization} {@link SmartLifecycle#start() starts} this bean
  * {@link #isAutoStartup() by default}. You can {@link SmartLifecycle#stop()} and {@link SmartLifecycle#start() restart}
  * this connection factory if needed.
+ * <p>
+ * Note that {@link JedisConnection} and its {@link JedisClusterConnection clustered variant} are not Thread-safe and
+ * instances should not be shared across threads. Refer to the
+ * <a href="https://github.com/redis/jedis/wiki/Getting-started#using-jedis-in-a-multithreaded-environment">Jedis
+ * documentation</a> for guidance on configuring Jedis in a multithreaded environment.
  *
  * @author Costin Leau
  * @author Thomas Darimont

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceClusterConnection.java

@@ -32,7 +32,6 @@ import java.util.Set;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-
 import org.springframework.beans.factory.DisposableBean;
 import org.springframework.dao.DataAccessException;
 import org.springframework.dao.InvalidDataAccessApiUsageException;
@@ -53,6 +52,13 @@ import org.springframework.util.ObjectUtils;
 /**
  * {@code RedisClusterConnection} implementation on top of <a href="https://github.com/mp911de/lettuce">Lettuce</a>
  * Redis client.
+ * <p>
+ * While the underlying Lettuce {@literal RedisClient} and {@literal StatefulRedisConnection} instances used by
+ * {@link LettuceClusterConnection} are Thread-safe, this class itself is not Thread-safe. Therefore, instances of
+ * {@link LettuceClusterConnection} should not be shared across multiple Threads when executing Redis commands and other
+ * operations. If optimal performance is required by your application(s), then we recommend direct access to the
+ * low-level, API provided by the underlying Lettuce client library (driver), where such Thread-safety guarantees can be
+ * made. Simply call {@link #getNativeConnection()} and use the native resource as required.
  *
  * @author Christoph Strobl
  * @author Mark Paluch
@@ -486,7 +492,6 @@ public class LettuceClusterConnection extends LettuceConnection
 		throw new InvalidDataAccessApiUsageException("MULTI is currently not supported in cluster mode");
 	}
 
-
 	public ClusterCommandExecutor getClusterCommandExecutor() {
 		return clusterCommandExecutor;
 	}

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceConnection.java

@@ -80,12 +80,12 @@ import org.springframework.util.ObjectUtils;
  * {@code RedisConnection} implementation on top of <a href="https://github.com/mp911de/lettuce">Lettuce</a> Redis
  * client.
  * <p>
- * WARNING: While the underlying Lettuce {@literal RedisClient} and {@literal StatefulRedisConnection} instances used by
- * {@link LettuceConnection} are Thread-safe, this class itself is not Thread-safe. Therefore, instances of {@link LettuceConnection}
- * should not be shared across multiple Threads when executing Redis commands and other operations. If optimal performance
- * is required by your application(s), then we recommend direct access to the low-level, API provided by the underlying
- * Lettuce client library (driver), where such Thread-safety guarantees can be made. Simply call {@link #getNativeConnection()}
- * and use the native resource as required.
+ * While the underlying Lettuce {@literal RedisClient} and {@literal StatefulRedisConnection} instances used by
+ * {@link LettuceConnection} are Thread-safe, this class itself is not Thread-safe. Therefore, instances of
+ * {@link LettuceConnection} should not be shared across multiple Threads when executing Redis commands and other
+ * operations. If optimal performance is required by your application(s), then we recommend direct access to the
+ * low-level, API provided by the underlying Lettuce client library (driver), where such Thread-safety guarantees can be
+ * made. Simply call {@link #getNativeConnection()} and use the native resource as required.
  *
  * @author Costin Leau
  * @author Jennifer Hickey

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceConnectionFactory.java

@@ -69,8 +69,10 @@ import org.springframework.util.StringUtils;
 /**
  * Connection factory creating <a href="https://github.com/mp911de/lettuce">Lettuce</a>-based connections.
  * <p>
- * This factory creates a new {@link LettuceConnection} on each call to {@link #getConnection()}. Multiple
- * {@link LettuceConnection}s share a single thread-safe native connection by default.
+ * This factory creates a new {@link LettuceConnection} on each call to {@link #getConnection()}. While multiple
+ * {@link LettuceConnection}s share a single thread-safe native connection by default, {@link LettuceConnection} and its
+ * {@link LettuceClusterConnection clustered variant} are not Thread-safe and instances should not be shared across
+ * threads.
  * <p>
  * The shared native connection is never closed by {@link LettuceConnection}, therefore it is not validated by default
  * on {@link #getConnection()}. Use {@link #setValidateConnection(boolean)} to change this behavior if necessary. If