Improve condition for returning type and avoiding NPE

spring-amqp/src/main/java/org/springframework/amqp/core/Binding.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 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.
@@ -30,6 +30,7 @@
  * @author Mark Fisher
  * @author Dave Syer
  * @author Gary Russell
+ * @author Ngoc Nhan
  *
  * @see AmqpAdmin
  */
@@ -74,7 +75,7 @@ public Binding(@Nullable Queue lazyQueue, @Nullable String destination, Destinat
 			String exchange, @Nullable String routingKey, @Nullable Map<String, Object> arguments) {
 
 		super(arguments);
-		Assert.isTrue(lazyQueue == null || destinationType.equals(DestinationType.QUEUE),
+		Assert.isTrue(lazyQueue == null || destinationType == DestinationType.QUEUE,
 				"'lazyQueue' must be null for destination type " + destinationType);
 		Assert.isTrue(lazyQueue != null || destination != null, "`destination` cannot be null");
 		this.lazyQueue = lazyQueue;

spring-amqp/src/main/java/org/springframework/amqp/support/converter/AbstractJavaTypeMapper.java

@@ -99,11 +99,9 @@ protected String retrieveHeader(MessageProperties properties, String headerName)
 	protected String retrieveHeaderAsString(MessageProperties properties, String headerName) {
 		Map<String, Object> headers = properties.getHeaders();
 		Object classIdFieldNameValue = headers.get(headerName);
-		String classId = null;
-		if (classIdFieldNameValue != null) {
-			classId = classIdFieldNameValue.toString();
-		}
-		return classId;
+		return classIdFieldNameValue != null
+				? classIdFieldNameValue.toString()
+				: null;
 	}
 
 	private void createReverseMap() {