diff --git a/spring-boot/src/main/java/org/springframework/boot/context/web/SpringBootServletInitializer.java b/spring-boot/src/main/java/org/springframework/boot/context/web/SpringBootServletInitializer.java
index e5ae60fd204..3e711be5bdb 100644
--- a/spring-boot/src/main/java/org/springframework/boot/context/web/SpringBootServletInitializer.java
+++ b/spring-boot/src/main/java/org/springframework/boot/context/web/SpringBootServletInitializer.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2014 the original author or authors.
+ * Copyright 2012-2015 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.
@@ -57,6 +57,7 @@ import org.springframework.web.context.WebApplicationContext;
  *
  * @author Dave Syer
  * @author Phillip Webb
+ * @author Andy Wilkinson
  * @see #configure(SpringApplicationBuilder)
  */
 public abstract class SpringBootServletInitializer implements WebApplicationInitializer {
@@ -84,6 +85,7 @@ public abstract class SpringBootServletInitializer implements WebApplicationInit
 	protected WebApplicationContext createRootApplicationContext(
 			ServletContext servletContext) {
 		SpringApplicationBuilder builder = new SpringApplicationBuilder();
+		builder.main(getClass());
 		ApplicationContext parent = getExistingRootWebApplicationContext(servletContext);
 		if (parent != null) {
 			this.logger.info("Root context already created (using as parent).");
diff --git a/spring-boot/src/test/java/org/springframework/boot/context/web/SpringBootServletInitializerTests.java b/spring-boot/src/test/java/org/springframework/boot/context/web/SpringBootServletInitializerTests.java
index 595b2aac5e5..ddd796b6bef 100644
--- a/spring-boot/src/test/java/org/springframework/boot/context/web/SpringBootServletInitializerTests.java
+++ b/spring-boot/src/test/java/org/springframework/boot/context/web/SpringBootServletInitializerTests.java
@@ -26,6 +26,7 @@ import org.hamcrest.Matcher;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ExpectedException;
+import org.springframework.beans.DirectFieldAccessor;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.context.annotation.Configuration;
@@ -33,12 +34,14 @@ import org.springframework.mock.web.MockServletContext;
 import org.springframework.web.context.WebApplicationContext;
 
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 
 /**
  * Tests for {@link SpringBootServletInitializerTests}.
  *
  * @author Phillip Webb
+ * @author Andy Wilkinson
  */
 public class SpringBootServletInitializerTests {
 
@@ -72,6 +75,17 @@ public class SpringBootServletInitializerTests {
 				equalToSet(Config.class, ErrorPageFilter.class));
 	}
 
+	@SuppressWarnings("rawtypes")
+	@Test
+	public void mainClassHasSensibleDefault() throws Exception {
+		new WithConfigurationAnnotation()
+				.createRootApplicationContext(this.servletContext);
+		Class mainApplicationClass = (Class<?>) new DirectFieldAccessor(this.application)
+				.getPropertyValue("mainApplicationClass");
+		assertThat(mainApplicationClass,
+				is(equalTo((Class) WithConfigurationAnnotation.class)));
+	}
+
 	private Matcher<? super Set<Object>> equalToSet(Object... items) {
 		Set<Object> set = new LinkedHashSet<Object>();
 		Collections.addAll(set, items);