Enable proxy target class for `MethodValidationPostProcessor`

Closes gh-8277

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/validation/ValidationAutoConfiguration.java

@@ -53,6 +53,7 @@ public class ValidationAutoConfiguration {
 	public MethodValidationPostProcessor methodValidationPostProcessor(
 			Validator validator) {
 		MethodValidationPostProcessor processor = new MethodValidationPostProcessor();
+		processor.setProxyTargetClass(true);
 		processor.setValidator(validator);
 		return processor;
 	}

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/validation/ValidationAutoConfigurationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 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.
@@ -18,6 +18,7 @@ package org.springframework.boot.autoconfigure.validation;
 
 import javax.validation.ConstraintViolationException;
 import javax.validation.Validator;
+import javax.validation.constraints.Min;
 import javax.validation.constraints.Size;
 
 import org.junit.After;
@@ -63,6 +64,17 @@ public class ValidationAutoConfigurationTests {
 		service.doSomething("KO");
 	}
 
+	@Test
+	public void validationUsesCglibProxy() {
+		load(DefaultAnotherSampleService.class);
+		assertThat(this.context.getBeansOfType(Validator.class)).hasSize(1);
+		DefaultAnotherSampleService service = this.context
+				.getBean(DefaultAnotherSampleService.class);
+		service.doSomething(42);
+		this.thrown.expect(ConstraintViolationException.class);
+		service.doSomething(2);
+	}
+
 	@Test
 	public void userDefinedMethodValidationPostProcessorTakesPrecedence() {
 		load(SampleConfiguration.class);
@@ -97,6 +109,20 @@ public class ValidationAutoConfigurationTests {
 
 	}
 
+	interface AnotherSampleService {
+
+		void doSomething(@Min(42) Integer counter);
+	}
+
+	@Validated
+	static class DefaultAnotherSampleService implements AnotherSampleService {
+
+		@Override
+		public void doSomething(Integer counter) {
+
+		}
+	}
+
 	@Configuration
 	static class SampleConfiguration {
 

spring-boot/src/test/java/org/springframework/boot/context/properties/ConfigurationPropertiesBindingPostProcessorTests.java

@@ -142,6 +142,18 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 		this.context.refresh();
 	}
 
+	@Test
+	public void testSuccessfulValidationWithInterface() {
+		MockEnvironment env = new MockEnvironment();
+		env.setProperty("test.foo", "bar");
+		this.context = new AnnotationConfigApplicationContext();
+		this.context.setEnvironment(env);
+		this.context.register(TestConfigurationWithValidationAndInterface.class);
+		this.context.refresh();
+		assertThat(this.context.getBean(ValidatedPropertiesImpl.class).getFoo())
+				.isEqualTo("bar");
+	}
+
 	@Test
 	public void testInitializersSeeBoundProperties() {
 		MockEnvironment env = new MockEnvironment();
@@ -486,6 +498,39 @@ public class ConfigurationPropertiesBindingPostProcessorTests {
 
 	}
 
+	@Configuration
+	@EnableConfigurationProperties
+	public static class TestConfigurationWithValidationAndInterface {
+
+		@Bean
+		public ValidatedPropertiesImpl testProperties() {
+			return new ValidatedPropertiesImpl();
+		}
+
+	}
+
+	interface ValidatedProperties {
+
+		String getFoo();
+	}
+
+	@ConfigurationProperties("test")
+	@Validated
+	public static class ValidatedPropertiesImpl implements ValidatedProperties {
+
+		@NotNull
+		private String foo;
+
+		@Override
+		public String getFoo() {
+			return this.foo;
+		}
+
+		public void setFoo(String foo) {
+			this.foo = foo;
+		}
+	}
+
 	@Configuration
 	@EnableConfigurationProperties
 	public static class TestConfigurationWithCustomValidator {