Demo readme improvements (#2833)

* appengine-api-1.0-sdk --> appengine-maven-plugin

* readme

* relative path instead of absolute

Co-authored-by: penmetsaa <penmetsaa@google.com>
Co-authored-by: Tijana Vislavski Gradina <tijanavg@google.com>

java/demo/README.md

@@ -1,4 +1,6 @@
-## Prerequisite:
+# Running the demo
+
+## 1. Install Google Cloud SDK
 
 ### Linux
 
@@ -16,6 +18,33 @@
 
 `$ gcloud components install app-engine-java`
 
-## How to regenerate the WAR, deploy and run in appengine?
+## 2. Add IDE Plugin
+
+### Intellij
+
+Install [Cloud Code Plugin for Intellij](https://plugins.jetbrains.com/plugin/8079-cloud-code)
+
+_If you have worked with the App Engine Plugin before,
+please [migrate](https://cloud.google.com/code/docs/intellij/migrate)._
+
+### Eclipse
+
+Install [Cloud Code Plugin for Eclipse](https://marketplace.eclipse.org/content/google-cloud-tools-eclipse)
+
+### Visual Studio Code
+
+Install [Cloud Code Plugin for Visual Studio Code](https://marketplace.visualstudio.com/items?itemName=GoogleCloudTools.cloudcode&ssr=false#overview)
+
+## 3. Run
+
+Most IDEs should autodetect your configuration after installing the plugin (and
+restart)
+
+![App Engine Run Config](.readme_res/App_Engine_Run_Config.png)
+
+## (Optional) Run Natively
+
+This is _not recommended_ with an IDE as you have to manage updating your
+artifacts yourself, it does not support live reload
 
 `$ mvn appengine:run`

java/demo/pom.xml

@@ -38,9 +38,9 @@
       <version>2022-07-20</version>
     </dependency>
     <dependency>
-      <artifactId>appengine-api-1.0-sdk</artifactId>
-      <groupId>com.google.appengine</groupId>
-      <version>2.0.8</version>
+      <artifactId>appengine-maven-plugin</artifactId>
+      <groupId>com.google.cloud.tools</groupId>
+      <version>2.4.4</version>
     </dependency>
     <dependency>
       <groupId>javax.servlet</groupId>