Address code review

- Remove unnecessary constructor in MaxRetryAttemptsPolicyExecution
- Use Supplier variant for logging methods
- Update Javadocs

Author: fmbenhassine

spring-core/src/main/java/org/springframework/core/retry/RetryListener.java

@@ -32,28 +32,30 @@ public interface RetryListener {
 
 	/**
 	 * Called before every retry attempt.
+	 * @param retryExecution the retry execution
 	 */
 	default void beforeRetry(RetryExecution retryExecution) {
-
 	}
 
 	/**
 	 * Called after the first successful retry attempt.
+	 * @param retryExecution the retry execution
 	 * @param result the result of the callback
-	 * @param <T> the type of the result
 	 */
-	default <T> void onRetrySuccess(RetryExecution retryExecution, T result) {
+	default void onRetrySuccess(RetryExecution retryExecution, Object result) {
 	}
 
 	/**
 	 * Called every time a retry attempt fails.
+	 * @param retryExecution the retry execution
 	 * @param throwable the throwable thrown by the callback
 	 */
 	default void onRetryFailure(RetryExecution retryExecution, Throwable throwable) {
 	}
 
 	/**
 	 * Called once the retry policy is exhausted.
+	 * @param retryExecution the retry execution
 	 * @param throwable the last throwable thrown by the callback
 	 */
 	default void onRetryPolicyExhaustion(RetryExecution retryExecution, Throwable throwable) {

spring-core/src/main/java/org/springframework/core/retry/RetryTemplate.java

@@ -130,33 +130,33 @@ public void setRetryListener(RetryListener retryListener) {
 		String callbackName = retryCallback.getName();
 		// initial attempt
 		try {
-			logger.debug("About to execute callback '" + callbackName + "'");
+			logger.debug(() -> "About to execute callback '" + callbackName + "'");
 			R result = retryCallback.run();
-			logger.debug("Callback '" + callbackName + "' executed successfully");
+			logger.debug(() -> "Callback '" + callbackName + "' executed successfully");
 			return result;
 		}
 		catch (Throwable initialException) {
-			logger.debug(initialException, () ->"Execution of callback '" + callbackName + "' failed, initiating the retry process");
+			logger.debug(initialException, () -> "Execution of callback '" + callbackName + "' failed, initiating the retry process");
 			// retry process starts here
 			RetryExecution retryExecution = this.retryPolicy.start();
 			BackOffExecution backOffExecution = this.backOffPolicy.start();
 			List<Throwable> suppressedExceptions = new ArrayList<>();
 
 			Throwable retryException = initialException;
 			while (retryExecution.shouldRetry(retryException)) {
-				logger.debug("About to retry callback '" + callbackName + "'");
+				logger.debug(() -> "About to retry callback '" + callbackName + "'");
 				try {
 					this.retryListener.beforeRetry(retryExecution);
 					R result = retryCallback.run();
 					this.retryListener.onRetrySuccess(retryExecution, result);
-					logger.debug("Callback '" + callbackName + "' retried successfully");
+					logger.debug(() -> "Callback '" + callbackName + "' retried successfully");
 					return result;
 				}
 				catch (Throwable currentAttemptException) {
 					this.retryListener.onRetryFailure(retryExecution, currentAttemptException);
 					try {
 						long duration = backOffExecution.nextBackOff();
-						logger.debug("Retry callback '" + callbackName + "' failed for " + currentAttemptException.getMessage() + ", backing off for " + duration + "ms");
+						logger.debug(() -> "Retry callback '" + callbackName + "' failed for " + currentAttemptException.getMessage() + ", backing off for " + duration + "ms");
 						Thread.sleep(duration);
 					}
 					catch (InterruptedException interruptedException) {

spring-core/src/main/java/org/springframework/core/retry/support/CompositeRetryListener.java

@@ -68,7 +68,7 @@ public void beforeRetry(RetryExecution retryExecution) {
 	}
 
 	@Override
-	public <T> void onRetrySuccess(RetryExecution retryExecution, T result) {
+	public void onRetrySuccess(RetryExecution retryExecution, Object result) {
 		this.listeners.forEach(listener -> listener.onRetrySuccess(retryExecution, result));
 	}
 

spring-core/src/main/java/org/springframework/core/retry/support/MaxRetryAttemptsPolicy.java

@@ -74,10 +74,6 @@ private class MaxRetryAttemptsPolicyExecution implements RetryExecution {
 
 		private int retryAttempts;
 
-		MaxRetryAttemptsPolicyExecution() {
-			this.retryAttempts = 0;
-		}
-
 		@Override
 		public boolean shouldRetry(Throwable throwable) {
 			return this.retryAttempts++ < MaxRetryAttemptsPolicy.this.maxRetryAttempts;

spring-core/src/main/java/org/springframework/core/retry/support/PredicateRetryPolicy.java

@@ -41,7 +41,7 @@ public PredicateRetryPolicy(Predicate<Throwable> predicate) {
 
 	/**
 	 * Start a new retry execution.
-	 * @return a fresh ready to be used
+	 * @return a fresh {@link RetryExecution} ready to be used
 	 */
 	public RetryExecution start() {
 		return this.predicate::test;