Ensure logPrefix is not null or blank in AbstractListenerWriteProcessor

spring-web/src/main/java/org/springframework/http/server/reactive/AbstractListenerWriteProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -27,6 +27,7 @@ import org.reactivestreams.Subscription;
 import org.springframework.core.log.LogDelegateFactory;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.StringUtils;
 
 /**
  * Abstract base class for {@code Processor} implementations that bridge between
@@ -87,13 +88,13 @@ public abstract class AbstractListenerWriteProcessor<T> implements Processor<T,
 	 * @since 5.1
 	 */
 	public AbstractListenerWriteProcessor(String logPrefix) {
-		this.logPrefix = logPrefix;
+		this.logPrefix = (StringUtils.hasText(logPrefix) ? logPrefix : "");
 		this.resultPublisher = new WriteResultPublisher(logPrefix);
 	}
 
 
 	/**
-	 * Create an instance with the given log prefix.
+	 * Get the configured log prefix.
 	 * @since 5.1
 	 */
 	public String getLogPrefix() {