Log warning if multiple @⁠RequestMapping annotations are declared

If multiple request mapping annotations are discovered, Spring MVC and
Spring WebFlux now log a warning similar to the following (without
newlines).

Multiple @⁠RequestMapping annotations found on
void org.example.MyController.put(), but only the first will be used:
[
@⁠org.springframework.web.bind.annotation.PutMapping(consumes={}, headers={}, name="", params={}, path={"/put"}, produces={}, value={"/put"}),
@⁠org.springframework.web.bind.annotation.PostMapping(consumes={}, headers={}, name="", params={}, path={"/put"}, produces={}, value={"/put"})
]

Closes gh-31962

spring-web/src/main/java/org/springframework/web/bind/annotation/DeleteMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -31,6 +31,13 @@ import org.springframework.core.annotation.AliasFor;
  * <p>Specifically, {@code @DeleteMapping} is a <em>composed annotation</em> that
  * acts as a shortcut for {@code @RequestMapping(method = RequestMethod.DELETE)}.
  *
+ * <p><strong>NOTE:</strong> This annotation cannot be used in conjunction with
+ * other {@code @RequestMapping} annotations that are declared on the same method.
+ * If multiple {@code @RequestMapping} annotations are detected on the same method,
+ * a warning will be logged, and only the first mapping will be used. This applies
+ * to {@code @RequestMapping} as well as composed {@code @RequestMapping} annotations
+ * such as {@code @GetMapping}, {@code @PostMapping}, etc.
+ *
  * @author Sam Brannen
  * @since 4.3
  * @see GetMapping

spring-web/src/main/java/org/springframework/web/bind/annotation/GetMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -31,6 +31,13 @@ import org.springframework.core.annotation.AliasFor;
  * <p>Specifically, {@code @GetMapping} is a <em>composed annotation</em> that
  * acts as a shortcut for {@code @RequestMapping(method = RequestMethod.GET)}.
  *
+ * <p><strong>NOTE:</strong> This annotation cannot be used in conjunction with
+ * other {@code @RequestMapping} annotations that are declared on the same method.
+ * If multiple {@code @RequestMapping} annotations are detected on the same method,
+ * a warning will be logged, and only the first mapping will be used. This applies
+ * to {@code @RequestMapping} as well as composed {@code @RequestMapping} annotations
+ * such as {@code @PutMapping}, {@code @PostMapping}, etc.
+ *
  * @author Sam Brannen
  * @since 4.3
  * @see PostMapping

spring-web/src/main/java/org/springframework/web/bind/annotation/PatchMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -31,6 +31,13 @@ import org.springframework.core.annotation.AliasFor;
  * <p>Specifically, {@code @PatchMapping} is a <em>composed annotation</em> that
  * acts as a shortcut for {@code @RequestMapping(method = RequestMethod.PATCH)}.
  *
+ * <p><strong>NOTE:</strong> This annotation cannot be used in conjunction with
+ * other {@code @RequestMapping} annotations that are declared on the same method.
+ * If multiple {@code @RequestMapping} annotations are detected on the same method,
+ * a warning will be logged, and only the first mapping will be used. This applies
+ * to {@code @RequestMapping} as well as composed {@code @RequestMapping} annotations
+ * such as {@code @GetMapping}, {@code @PostMapping}, etc.
+ *
  * @author Sam Brannen
  * @since 4.3
  * @see GetMapping

spring-web/src/main/java/org/springframework/web/bind/annotation/PostMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -31,6 +31,13 @@ import org.springframework.core.annotation.AliasFor;
  * <p>Specifically, {@code @PostMapping} is a <em>composed annotation</em> that
  * acts as a shortcut for {@code @RequestMapping(method = RequestMethod.POST)}.
  *
+ * <p><strong>NOTE:</strong> This annotation cannot be used in conjunction with
+ * other {@code @RequestMapping} annotations that are declared on the same method.
+ * If multiple {@code @RequestMapping} annotations are detected on the same method,
+ * a warning will be logged, and only the first mapping will be used. This applies
+ * to {@code @RequestMapping} as well as composed {@code @RequestMapping} annotations
+ * such as {@code @GetMapping}, {@code @PutMapping}, etc.
+ *
  * @author Sam Brannen
  * @since 4.3
  * @see GetMapping

spring-web/src/main/java/org/springframework/web/bind/annotation/PutMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -31,6 +31,13 @@ import org.springframework.core.annotation.AliasFor;
  * <p>Specifically, {@code @PutMapping} is a <em>composed annotation</em> that
  * acts as a shortcut for {@code @RequestMapping(method = RequestMethod.PUT)}.
  *
+ * <p><strong>NOTE:</strong> This annotation cannot be used in conjunction with
+ * other {@code @RequestMapping} annotations that are declared on the same method.
+ * If multiple {@code @RequestMapping} annotations are detected on the same method,
+ * a warning will be logged, and only the first mapping will be used. This applies
+ * to {@code @RequestMapping} as well as composed {@code @RequestMapping} annotations
+ * such as {@code @GetMapping}, {@code @PostMapping}, etc.
+ *
  * @author Sam Brannen
  * @since 4.3
  * @see GetMapping

spring-web/src/main/java/org/springframework/web/bind/annotation/RequestMapping.java

@@ -54,6 +54,13 @@ import org.springframework.core.annotation.AliasFor;
  * {@link PutMapping @PutMapping}, {@link DeleteMapping @DeleteMapping}, or
  * {@link PatchMapping @PatchMapping}.
  *
+ * <p><strong>NOTE:</strong> This annotation cannot be used in conjunction with
+ * other {@code @RequestMapping} annotations that are declared on the same element
+ * (class, interface, or method). If multiple {@code @RequestMapping} annotations
+ * are detected on the same element, a warning will be logged, and only the first
+ * mapping will be used. This also applies to composed {@code @RequestMapping}
+ * annotations such as {@code @GetMapping}, {@code @PostMapping}, etc.
+ *
  * <p><b>NOTE:</b> When using controller interfaces (e.g. for AOP proxying),
  * make sure to consistently put <i>all</i> your mapping annotations &mdash; such
  * as {@code @RequestMapping} and {@code @SessionAttributes} &mdash; on