Merge branch '5.3.x'

spring-aop/src/test/java/org/springframework/aop/framework/AopProxyUtilsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2022 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.
@@ -19,6 +19,7 @@ package org.springframework.aop.framework;
 import java.lang.reflect.Proxy;
 import java.util.Arrays;
 import java.util.List;
+import java.util.function.Supplier;
 
 import org.junit.jupiter.api.Test;
 
@@ -32,6 +33,7 @@ import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException
 /**
  * @author Rod Johnson
  * @author Chris Beams
+ * @author Sam Brannen
  */
 public class AopProxyUtilsTests {
 
@@ -132,4 +134,61 @@ public class AopProxyUtilsTests {
 				AopProxyUtils.proxiedUserInterfaces(proxy));
 	}
 
+	@Test
+	void isLambda() {
+		assertIsLambda(AopProxyUtilsTests.staticLambdaExpression);
+		assertIsLambda(AopProxyUtilsTests::staticStringFactory);
+
+		assertIsLambda(this.instanceLambdaExpression);
+		assertIsLambda(this::instanceStringFactory);
+	}
+
+	@Test
+	void isNotLambda() {
+		assertIsNotLambda(new EnigmaSupplier());
+
+		assertIsNotLambda(new Supplier<String>() {
+			@Override
+			public String get() {
+				return "anonymous inner class";
+			}
+		});
+
+		assertIsNotLambda(new Fake$$LambdaSupplier());
+	}
+
+	private static void assertIsLambda(Supplier<String> supplier) {
+		assertThat(AopProxyUtils.isLambda(supplier.getClass())).isTrue();
+	}
+
+	private static void assertIsNotLambda(Supplier<String> supplier) {
+		assertThat(AopProxyUtils.isLambda(supplier.getClass())).isFalse();
+	}
+
+	private static final Supplier<String> staticLambdaExpression = () -> "static lambda expression";
+
+	private final Supplier<String> instanceLambdaExpression = () -> "instance lambda expressions";
+
+	private static String staticStringFactory() {
+		return "static string factory";
+	}
+
+	private String instanceStringFactory() {
+		return "instance string factory";
+	}
+
+	private static class EnigmaSupplier implements Supplier<String> {
+		@Override
+		public String get() {
+			return "enigma";
+		}
+	}
+
+	private static class Fake$$LambdaSupplier implements Supplier<String> {
+		@Override
+		public String get() {
+			return "fake lambda";
+		}
+	}
+
 }