+ update return signature for jedis exec

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/connection/DefaultStringRedisConnection.java

@@ -116,7 +116,7 @@ public class DefaultStringRedisConnection implements StringRedisConnection {
 		return delegate.echo(message);
 	}
 
-	public List<Object> exec() {
+	public List<byte[]> exec() {
 		return delegate.exec();
 	}
 

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/connection/RedisTxCommands.java

@@ -27,7 +27,7 @@ public interface RedisTxCommands {
 
 	void multi();
 
-	List<Object> exec();
+	List<byte[]> exec();
 
 	void discard();
 

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

@@ -511,14 +511,19 @@ public class JedisConnection implements RedisConnection {
 		}
 	}
 
+	@SuppressWarnings("unchecked")
 	@Override
-	public List<Object> exec() {
+	public List<byte[]> exec() {
 		try {
 			if (isPipelined()) {
 				pipeline.exec();
 				return null;
 			}
-			return transaction.exec();
+			List execute = transaction.exec();
+			if (execute != null && !execute.isEmpty()) {
+				return (List<byte[]>) execute;
+			}
+			return Collections.emptyList();
 		} catch (Exception ex) {
 			throw convertJedisAccessException(ex);
 		}

spring-data-redis/src/main/java/org/springframework/data/keyvalue/redis/connection/jredis/JredisConnection.java

@@ -267,7 +267,7 @@ public class JredisConnection implements RedisConnection {
 	}
 
 	@Override
-	public List<Object> exec() {
+	public List<byte[]> exec() {
 		throw new UnsupportedOperationException();
 	}