Add warning for missing optional keys in DefaultJobParametersValidator

Before this commit, the DefaultJobParametersValidator
was failing when an optional key is missing.

This commit changes the default validator to only log
a warning in this case.

Resolves #4073

spring-batch-core/src/main/java/org/springframework/batch/core/job/DefaultJobParametersValidator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2018 the original author or authors.
+ * Copyright 2012-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,9 @@
 import java.util.HashSet;
 import java.util.Set;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 import org.springframework.batch.core.JobParameters;
 import org.springframework.batch.core.JobParametersInvalidException;
 import org.springframework.batch.core.JobParametersValidator;
@@ -36,6 +39,8 @@
  */
 public class DefaultJobParametersValidator implements JobParametersValidator, InitializingBean {
 
+	private static final Log logger = LogFactory.getLog(DefaultJobParametersValidator.class);
+
 	private Collection<String> requiredKeys;
 
 	private Collection<String> optionalKeys;
@@ -100,7 +105,7 @@ public void validate(@Nullable JobParameters parameters) throws JobParametersInv
 				}
 			}
 			if (!missingKeys.isEmpty()) {
-				throw new JobParametersInvalidException(
+				logger.warn(
 						"The JobParameters contains keys that are not explicitly optional or required: " + missingKeys);
 			}
 

spring-batch-core/src/test/java/org/springframework/batch/core/job/DefaultJobParametersValidatorTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2009-2022 the original author or authors.
+ * Copyright 2009-2023 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@
 import org.springframework.batch.core.JobParametersBuilder;
 import org.springframework.batch.core.JobParametersInvalidException;
 
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
 class DefaultJobParametersValidatorTests {
@@ -59,7 +60,7 @@ void testValidateOptionalValues() throws Exception {
 	void testValidateOptionalWithImplicitRequiredKey() {
 		validator.setOptionalKeys(new String[] { "name", "value" });
 		JobParameters jobParameters = new JobParametersBuilder().addString("foo", "bar").toJobParameters();
-		assertThrows(JobParametersInvalidException.class, () -> validator.validate(jobParameters));
+		assertDoesNotThrow(() -> validator.validate(jobParameters));
 	}
 
 	@Test