Make it possible to disable the BackgroundPreinitializer

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java

@@ -42,6 +42,7 @@
  *
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @author Artsiom Yudovin
  * @since 1.3.0
  */
 @Order(LoggingApplicationListener.DEFAULT_ORDER + 1)
@@ -57,7 +58,13 @@ public class BackgroundPreinitializer
 	public void onApplicationEvent(SpringApplicationEvent event) {
 		if (event instanceof ApplicationStartingEvent
 				&& preinitializationStarted.compareAndSet(false, true)) {
-			performPreinitialization();
+
+			if (Boolean.getBoolean("spring.backgroundpreinitializer.ignore")) {
+				performPreinitialization(this.perform());
+			}
+			else {
+				performPreinitializationBackground(this.perform());
+			}
 		}
 		if ((event instanceof ApplicationReadyEvent
 				|| event instanceof ApplicationFailedEvent)
@@ -71,31 +78,21 @@ public void onApplicationEvent(SpringApplicationEvent event) {
 		}
 	}
 
-	private void performPreinitialization() {
+	private void performPreinitialization(Runnable runnable) {
 		try {
-			Thread thread = new Thread(new Runnable() {
-
-				@Override
-				public void run() {
-					runSafely(new ConversionServiceInitializer());
-					runSafely(new ValidationInitializer());
-					runSafely(new MessageConverterInitializer());
-					runSafely(new MBeanFactoryInitializer());
-					runSafely(new JacksonInitializer());
-					runSafely(new CharsetInitializer());
-					preinitializationComplete.countDown();
-				}
-
-				public void runSafely(Runnable runnable) {
-					try {
-						runnable.run();
-					}
-					catch (Throwable ex) {
-						// Ignore
-					}
-				}
+			runnable.run();
+		}
+		catch (Exception ex) {
+			// This will fail on GAE where creating threads is prohibited. We can safely
+			// continue but startup will be slightly slower as the initialization will now
+			// happen on the main thread.
+			preinitializationComplete.countDown();
+		}
+	}
 
-			}, "background-preinit");
+	private void performPreinitializationBackground(Runnable runnable) {
+		try {
+			Thread thread = new Thread(runnable, "background-preinit");
 			thread.start();
 		}
 		catch (Exception ex) {
@@ -106,6 +103,32 @@ public void runSafely(Runnable runnable) {
 		}
 	}
 
+	private Runnable perform() {
+		return new Runnable() {
+
+			@Override
+			public void run() {
+				runSafely(new ConversionServiceInitializer());
+				runSafely(new ValidationInitializer());
+				runSafely(new MessageConverterInitializer());
+				runSafely(new MBeanFactoryInitializer());
+				runSafely(new JacksonInitializer());
+				runSafely(new CharsetInitializer());
+				preinitializationComplete.countDown();
+			}
+
+			public void runSafely(Runnable runnable) {
+				try {
+					runnable.run();
+				}
+				catch (Throwable ex) {
+					// Ignore
+				}
+			}
+
+		};
+	}
+
 	/**
 	 * Early initializer for Spring MessageConverters.
 	 */

spring-boot-project/spring-boot-docs/src/main/asciidoc/appendix-application-properties.adoc

@@ -69,6 +69,7 @@ content into your application. Rather, pick only the properties that you need.
 
 	# SPRING CORE
 	spring.beaninfo.ignore=true # Whether to skip search of BeanInfo classes.
+    spring.backgroundpreinitializer.ignore=true # Whether background preinitializer should be ignored.
 
 	# SPRING CACHE ({sc-spring-boot-autoconfigure}/cache/CacheProperties.{sc-ext}[CacheProperties])
 	spring.cache.cache-names= # Comma-separated list of cache names to create if supported by the underlying cache manager.