Document that Cassandra policy classes must have a default constructor

Closes gh-14461

Author: wilkinsona

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/cassandra/CassandraProperties.java

@@ -74,7 +74,7 @@ public class CassandraProperties {
 	private Compression compression = Compression.NONE;
 
 	/**
-	 * Class name of the load balancing policy.
+	 * Class name of the load balancing policy. The class must have a default constructor.
 	 */
 	private Class<? extends LoadBalancingPolicy> loadBalancingPolicy;
 
@@ -94,12 +94,12 @@ public class CassandraProperties {
 	private int fetchSize = QueryOptions.DEFAULT_FETCH_SIZE;
 
 	/**
-	 * Reconnection policy class.
+	 * Class name of the reconnection policy. The class must have a default constructor.
 	 */
 	private Class<? extends ReconnectionPolicy> reconnectionPolicy;
 
 	/**
-	 * Class name of the retry policy.
+	 * Class name of the retry policy. The class must have a default constructor.
 	 */
 	private Class<? extends RetryPolicy> retryPolicy;
 

spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -558,13 +558,13 @@ content into your application; rather pick only the properties that you need.
 	spring.data.cassandra.contact-points=localhost # Comma-separated list of cluster node addresses.
 	spring.data.cassandra.fetch-size= # Queries default fetch size.
 	spring.data.cassandra.keyspace-name= # Keyspace name to use.
-	spring.data.cassandra.load-balancing-policy= # Class name of the load balancing policy.
+	spring.data.cassandra.load-balancing-policy= # Class name of the load balancing policy. The class must have a default constructor.
 	spring.data.cassandra.port= # Port of the Cassandra server.
 	spring.data.cassandra.password= # Login password of the server.
 	spring.data.cassandra.read-timeout-millis= # Socket option: read time out.
-	spring.data.cassandra.reconnection-policy= # Reconnection policy class.
+	spring.data.cassandra.reconnection-policy= # Class name of the reconnection policy. The class must have a default constructor.
 	spring.data.cassandra.repositories.enabled= # Enable Cassandra repositories.
-	spring.data.cassandra.retry-policy= # Class name of the retry policy.
+	spring.data.cassandra.retry-policy= # Class name of the retry policy. The class must have a default constructor.
 	spring.data.cassandra.serial-consistency-level= # Queries serial consistency level.
 	spring.data.cassandra.schema-action=none # Schema action to take at startup.
 	spring.data.cassandra.ssl=false # Enable SSL support.