Strong references to mapped exception handler methods

Issue: SPR-15907

spring-messaging/src/main/java/org/springframework/messaging/handler/invocation/AbstractExceptionHandlerMethodResolver.java

@@ -19,6 +19,7 @@ package org.springframework.messaging.handler.invocation;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -38,7 +39,7 @@ import org.springframework.util.ConcurrentReferenceHashMap;
  */
 public abstract class AbstractExceptionHandlerMethodResolver {
 
-	private final Map<Class<? extends Throwable>, Method> mappedMethods = new ConcurrentReferenceHashMap<>(16);
+	private final Map<Class<? extends Throwable>, Method> mappedMethods = new HashMap<>(16);
 
 	private final Map<Class<? extends Throwable>, Method> exceptionLookupCache = new ConcurrentReferenceHashMap<>(16);
 
@@ -64,7 +65,9 @@ public abstract class AbstractExceptionHandlerMethodResolver {
 				result.add((Class<? extends Throwable>) paramType);
 			}
 		}
-		Assert.notEmpty(result, "No exception types mapped to {" + method + "}");
+		if (result.isEmpty()) {
+			throw new IllegalStateException("No exception types mapped to " + method);
+		}
 		return result;
 	}
 
@@ -73,7 +76,7 @@ public abstract class AbstractExceptionHandlerMethodResolver {
 	 * Whether the contained type has any exception mappings.
 	 */
 	public boolean hasExceptionMappings() {
-		return (this.mappedMethods.size() > 0);
+		return !this.mappedMethods.isEmpty();
 	}
 
 	/**

spring-messaging/src/test/java/org/springframework/messaging/handler/annotation/support/AnnotationExceptionHandlerMethodResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2016 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -94,7 +94,7 @@ public class AnnotationExceptionHandlerMethodResolverTests {
 		new AnnotationExceptionHandlerMethodResolver(AmbiguousController.class);
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test(expected = IllegalStateException.class)
 	public void noExceptionMapping() {
 		new AnnotationExceptionHandlerMethodResolver(NoExceptionController.class);
 	}

spring-web/src/main/java/org/springframework/web/method/annotation/ExceptionHandlerMethodResolver.java

@@ -20,6 +20,7 @@ import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -50,7 +51,7 @@ public class ExceptionHandlerMethodResolver {
 			(AnnotationUtils.findAnnotation(method, ExceptionHandler.class) != null);
 
 
-	private final Map<Class<? extends Throwable>, Method> mappedMethods = new ConcurrentReferenceHashMap<>(16);
+	private final Map<Class<? extends Throwable>, Method> mappedMethods = new HashMap<>(16);
 
 	private final Map<Class<? extends Throwable>, Method> exceptionLookupCache = new ConcurrentReferenceHashMap<>(16);
 
@@ -83,7 +84,9 @@ public class ExceptionHandlerMethodResolver {
 				}
 			}
 		}
-		Assert.notEmpty(result, "No exception types mapped to {" + method + "}");
+		if (result.isEmpty()) {
+			throw new IllegalStateException("No exception types mapped to " + method);
+		}
 		return result;
 	}
 

spring-web/src/test/java/org/springframework/web/method/annotation/ExceptionHandlerMethodResolverTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2017 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.
@@ -88,11 +88,12 @@ public class ExceptionHandlerMethodResolverTests {
 		new ExceptionHandlerMethodResolver(AmbiguousController.class);
 	}
 
-	@Test(expected = IllegalArgumentException.class)
+	@Test(expected = IllegalStateException.class)
 	public void noExceptionMapping() {
 		new ExceptionHandlerMethodResolver(NoExceptionController.class);
 	}
 
+
 	@Controller
 	static class ExceptionController {
 
@@ -111,6 +112,7 @@ public class ExceptionHandlerMethodResolverTests {
 		}
 	}
 
+
 	@Controller
 	static class InheritedController extends ExceptionController {
 
@@ -119,6 +121,7 @@ public class ExceptionHandlerMethodResolverTests {
 		}
 	}
 
+
 	@Controller
 	static class AmbiguousController {
 
@@ -136,6 +139,7 @@ public class ExceptionHandlerMethodResolverTests {
 		}
 	}
 
+
 	@Controller
 	static class NoExceptionController {