Remove pre Java8 option 'MaxPermSize'

Closes gh-3487

CONTRIBUTING.adoc

@@ -67,7 +67,7 @@ The project can be built from the root directory using the standard maven comman
 ----
 
 NOTE: You may need to increase the amount of memory available to Maven by setting
-a `MAVEN_OPTS` environment variable with the value `-Xmx512m -XX:MaxPermSize=128m`
+a `MAVEN_OPTS` environment variable with the value `-Xmx512m`
 
 If you are rebuilding often, you might also want to skip the tests until you are ready
 to submit a pull request:
@@ -118,7 +118,7 @@ Once the build has been prepared, you can run a full build using the following c
 
 NOTE: As for the standard build, you may need to increase the amount of memory available
 to Maven by setting a `MAVEN_OPTS` environment variable with the value
-`-Xmx512m -XX:MaxPermSize=128m`. We generate more artifacts when running the full build
+`-Xmx512m`. We generate more artifacts when running the full build
 (such as Javadoc jars), so you may find the process a little slower than the standard build.
 
 

README.adoc

@@ -101,7 +101,7 @@ v3.0.5 or above. You also need JDK 1.8 (although Boot applications can run on Ja
 ----
 
 NOTE: You may need to increase the amount of memory available to Maven by setting
-a `MAVEN_OPTS` environment variable with the value `-Xmx512m -XX:MaxPermSize=128m`. Remember
+a `MAVEN_OPTS` environment variable with the value `-Xmx512m`. Remember
 to set the corresponding property in your IDE as well if you are building and running
 tests there (e.g. in Eclipse go to `Preferences->Java->Installed JREs` and edit the
 JRE definition so that all processes are launched with those arguments).

spring-boot-parent/pom.xml

@@ -473,7 +473,7 @@
 						<java.security.egd>file:/dev/./urandom</java.security.egd>
 						<java.awt.headless>true</java.awt.headless>
 					</systemPropertyVariables>
-					<argLine>-Xmx1024m -XX:MaxPermSize=256m</argLine>
+					<argLine>-Xmx1024m</argLine>
 				</configuration>
 			</plugin>
 			<plugin>