LocalValidatorFactoryBean properly supports unwrap at ValidatorFactory level

Also documents limitation for Bean Validation 2.0's getClockProvider() method.

Issue: SPR-15561
Issue: SPR-13482

spring-context/src/test/java/org/springframework/validation/beanvalidation/SpringValidatorAdapterTests.java

@@ -27,6 +27,7 @@ import javax.validation.ConstraintValidator;
 import javax.validation.ConstraintValidatorContext;
 import javax.validation.Payload;
 import javax.validation.Validation;
+import javax.validation.Validator;
 import javax.validation.constraints.Pattern;
 import javax.validation.constraints.Size;
 
@@ -51,8 +52,9 @@ import static org.junit.Assert.*;
  */
 public class SpringValidatorAdapterTests {
 
-	private final SpringValidatorAdapter validatorAdapter = new SpringValidatorAdapter(
-			Validation.buildDefaultValidatorFactory().getValidator());
+	private final Validator nativeValidator = Validation.buildDefaultValidatorFactory().getValidator();
+
+	private final SpringValidatorAdapter validatorAdapter = new SpringValidatorAdapter(nativeValidator);
 
 	private final StaticMessageSource messageSource = new StaticMessageSource();
 
@@ -66,6 +68,12 @@ public class SpringValidatorAdapterTests {
 	}
 
 
+	@Test
+	public void testUnwrap() {
+		Validator nativeValidator = validatorAdapter.unwrap(Validator.class);
+		assertSame(this.nativeValidator, nativeValidator);
+	}
+
 	@Test  // SPR-13406
 	public void testNoStringArgumentValue() {
 		TestBean testBean = new TestBean();

spring-context/src/test/java/org/springframework/validation/beanvalidation/ValidatorFactoryTests.java

@@ -33,9 +33,12 @@ import javax.validation.ConstraintValidatorContext;
 import javax.validation.ConstraintViolation;
 import javax.validation.Payload;
 import javax.validation.Valid;
+import javax.validation.Validator;
+import javax.validation.ValidatorFactory;
 import javax.validation.constraints.NotNull;
 
 import org.hibernate.validator.HibernateValidator;
+import org.hibernate.validator.HibernateValidatorFactory;
 import org.junit.Test;
 
 import org.springframework.beans.factory.annotation.Autowired;
@@ -75,6 +78,12 @@ public class ValidatorFactoryTests {
 				fail("Invalid constraint violation with path '" + path + "'");
 			}
 		}
+
+		Validator nativeValidator = validator.unwrap(Validator.class);
+		assertTrue(nativeValidator.getClass().getName().startsWith("org.hibernate"));
+		assertTrue(validator.unwrap(ValidatorFactory.class) instanceof HibernateValidatorFactory);
+		assertTrue(validator.unwrap(HibernateValidatorFactory.class) instanceof HibernateValidatorFactory);
+
 		validator.destroy();
 	}
 
@@ -96,6 +105,12 @@ public class ValidatorFactoryTests {
 				fail("Invalid constraint violation with path '" + path + "'");
 			}
 		}
+
+		Validator nativeValidator = validator.unwrap(Validator.class);
+		assertTrue(nativeValidator.getClass().getName().startsWith("org.hibernate"));
+		assertTrue(validator.unwrap(ValidatorFactory.class) instanceof HibernateValidatorFactory);
+		assertTrue(validator.unwrap(HibernateValidatorFactory.class) instanceof HibernateValidatorFactory);
+
 		validator.destroy();
 	}
 
@@ -465,7 +480,7 @@ public class ValidatorFactoryTests {
 
 		String message() default "Should not be X";
 
-		Class<?>[] groups() default { };
+		Class<?>[] groups() default {};
 
 		Class<? extends Payload>[] payload() default {};
 	}