Remove unused deduceFromApplicationContext and supporting code

Closes gh-31218

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/WebApplicationType.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2019 the original author or authors.
+ * Copyright 2012-2022 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.
@@ -54,10 +54,6 @@ public enum WebApplicationType {
 
 	private static final String JERSEY_INDICATOR_CLASS = "org.glassfish.jersey.servlet.ServletContainer";
 
-	private static final String SERVLET_APPLICATION_CONTEXT_CLASS = "org.springframework.web.context.WebApplicationContext";
-
-	private static final String REACTIVE_APPLICATION_CONTEXT_CLASS = "org.springframework.boot.web.reactive.context.ReactiveWebApplicationContext";
-
 	static WebApplicationType deduceFromClasspath() {
 		if (ClassUtils.isPresent(WEBFLUX_INDICATOR_CLASS, null) && !ClassUtils.isPresent(WEBMVC_INDICATOR_CLASS, null)
 				&& !ClassUtils.isPresent(JERSEY_INDICATOR_CLASS, null)) {
@@ -71,23 +67,4 @@ static WebApplicationType deduceFromClasspath() {
 		return WebApplicationType.SERVLET;
 	}
 
-	static WebApplicationType deduceFromApplicationContext(Class<?> applicationContextClass) {
-		if (isAssignable(SERVLET_APPLICATION_CONTEXT_CLASS, applicationContextClass)) {
-			return WebApplicationType.SERVLET;
-		}
-		if (isAssignable(REACTIVE_APPLICATION_CONTEXT_CLASS, applicationContextClass)) {
-			return WebApplicationType.REACTIVE;
-		}
-		return WebApplicationType.NONE;
-	}
-
-	private static boolean isAssignable(String target, Class<?> type) {
-		try {
-			return ClassUtils.resolveClassName(target, null).isAssignableFrom(type);
-		}
-		catch (Throwable ex) {
-			return false;
-		}
-	}
-
 }