Add JAVA_OPTS advice to some docs

spring-boot-docs/src/main/asciidoc/using-spring-boot.adoc

@@ -555,8 +555,6 @@ This allows you to attach a debugger to your packaged application:
 	       -jar target/myproject-0.0.1-SNAPSHOT.jar
 ----
 
-
-
 [[using-boot-running-with-the-maven-plugin]]
 === Using the Maven plugin
 The Spring Boot Maven plugin includes a `run` goal which can be used to quickly compile
@@ -568,7 +566,13 @@ resources for instant ``hot'' reload.
 	$ mvn spring-boot:run
 ----
 
+Useful operating system environment variable:
 
+```
+$ export MAVEN_OPTS=-Xmx1024m -XX:MaxPermSize=128M -Djava.security.egd=file:/dev/./urandom
+```
+
+(The "egd" setting is to speed up Tomcat startup by giving it a faster source of entropy for session keys.)
 
 [[using-boot-running-with-the-gradle-plugin]]
 === Using the Gradle plugin
@@ -581,6 +585,11 @@ the `spring-boot-plugin`
 	$ gradle bootRun
 ----
 
+Useful operating system environment variable:
+
+```
+$ export JAVA_OPTS=-Xmx1024m -XX:MaxPermSize=128M -Djava.security.egd=file:/dev/./urandom
+```
 
 
 [[using-boot-hot-swapping]]