Refine contribution #4668

Before this commit, an assertion was enforcing
that when a skip limit is provided, then at least
one skippable exception is defined.

Since the default value of skip limit was changed
to 10 in fd45d32, that assertion is now replaced
with a log message at debug level.

Related to #4661

Author: fmbenhassine

spring-batch-core/src/main/java/org/springframework/batch/core/step/builder/FaultTolerantStepBuilder.java

@@ -555,8 +555,11 @@ protected SkipPolicy createSkipPolicy() {
 		map.put(ForceRollbackForWriteSkipException.class, true);
 		LimitCheckingItemSkipPolicy limitCheckingItemSkipPolicy = new LimitCheckingItemSkipPolicy(skipLimit, map);
 		if (skipPolicy == null) {
-			Assert.state(!(skippableExceptionClasses.isEmpty() && skipLimit > 0),
-					"If a skip limit is provided then skippable exceptions must also be specified");
+			if (skippableExceptionClasses.isEmpty() && skipLimit > 0) {
+				logger.debug(String.format(
+						"A skip limit of %s is set but no skippable exceptions are defined. Consider defining skippable exceptions.",
+						skipLimit));
+			}
 			skipPolicy = limitCheckingItemSkipPolicy;
 		}
 		else if (limitCheckingItemSkipPolicy != null) {