Fix JavaDocs for constants

Author: artembilan

spring-kafka/src/main/java/org/springframework/kafka/core/DefaultKafkaProducerFactory.java

@@ -82,11 +82,15 @@
  * @author Gary Russell
  * @author Murali Reddy
  * @author Nakul Mishra
+ * @author Artem Bilan
  */
 public class DefaultKafkaProducerFactory<K, V> implements ProducerFactory<K, V>, ApplicationContextAware,
 		ApplicationListener<ContextStoppedEvent>, DisposableBean {
 
-	private static final Duration DEFAULT_PHYSICAL_CLOSE_TIMEOUT = Duration.ofSeconds(30);
+	/**
+	 * The default close timeout duration as 30 seconds.
+	 */
+	public static final Duration DEFAULT_PHYSICAL_CLOSE_TIMEOUT = Duration.ofSeconds(30);
 
 	private static final Log logger = LogFactory.getLog(DefaultKafkaProducerFactory.class); // NOSONAR
 
@@ -149,7 +153,7 @@ public void setValueSerializer(@Nullable Serializer<V> valueSerializer) {
 
 	/**
 	 * The time to wait when physically closing the producer (when {@link #stop()} or {@link #destroy()} is invoked).
-	 * Specified in seconds; default {@value #DEFAULT_PHYSICAL_CLOSE_TIMEOUT}.
+	 * Specified in seconds; default {@link #DEFAULT_PHYSICAL_CLOSE_TIMEOUT}.
 	 * @param physicalCloseTimeout the timeout in seconds.
 	 * @since 1.0.7
 	 */

spring-kafka/src/main/java/org/springframework/kafka/core/KafkaAdmin.java

@@ -52,12 +52,16 @@
  * in the application context.
  *
  * @author Gary Russell
+ * @author Artem Bilan
  *
  * @since 1.3
  */
 public class KafkaAdmin implements ApplicationContextAware, SmartInitializingSingleton {
 
-	private static final Duration DEFAULT_CLOSE_TIMEOUT = Duration.ofSeconds(10);
+	/**
+	 * The default close timeout duration as 10 seconds.
+	 */
+	public static final Duration DEFAULT_CLOSE_TIMEOUT = Duration.ofSeconds(10);
 
 	private static final int DEFAULT_OPERATION_TIMEOUT = 30;
 
@@ -92,7 +96,7 @@ public void setApplicationContext(ApplicationContext applicationContext) throws
 	}
 
 	/**
-	 * Set the close timeout in seconds. Defaults to {@value #DEFAULT_CLOSE_TIMEOUT} seconds.
+	 * Set the close timeout in seconds. Defaults to {@link #DEFAULT_CLOSE_TIMEOUT} seconds.
 	 * @param closeTimeout the timeout.
 	 */
 	public void setCloseTimeout(int closeTimeout) {