How to upgrade Google App Engine servlet-api-2.5 to servlet-api-3.1?

Here is a full example given here: https://github.com/GoogleCloudPlatform/getting-started-java/tree/master/appengine-standard-java8/helloworld

Running procedure is also attached.

For Gradle Users:

For non-maven users, you can use gradle.

In gradle build file, line number 39 denotes: https://github.com/GoogleCloudPlatform/getting-started-java/blob/master/appengine-standard-java8/helloworld/build.gradle#L39

providedCompile 'javax.servlet:javax.servlet-api:3.1.0'

Running locally:

gradle appengineRun

If you do not have gradle installed, you can run using ./gradlew appengineRun.

To use visit: http://localhost:8080/

For Maven Users

In pom.xml, line number 62 to 70 denotes that it is using servlet version 3.1.0: https://github.com/GoogleCloudPlatform/getting-started-java/blob/master/appengine-standard-java8/helloworld/pom.xml#L66

<!-- [START servlet] -->
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>javax.servlet-api</artifactId>
  <version>3.1.0</version>
  <type>jar</type>
  <scope>provided</scope>
</dependency>
<!-- [END servlet] -->

Resource Link: https://stackoverflow.com/a/44901461/2293534