Update README.md

README.md

@@ -3,34 +3,33 @@
 ![GitHub tag checks state](https://img.shields.io/github/checks-status/softleader/jib-jvm-flags-extension-maven/main)
 ![GitHub issues](https://img.shields.io/github/issues-raw/softleader/jib-jvm-flags-extension-maven)
 
-# Jib JVM Flags extension
+# Jib JVM Flags Extension
 
-A [Jib](https://github.com/GoogleContainerTools/jib) [extension](https://github.com/GoogleContainerTools/jib-extensions) outputs the configured `jvmFlags` into the `/app/jib-jvm-flags-file` file, allowing a [custom entrypoint](https://github.com/GoogleContainerTools/jib/tree/master/jib-maven-plugin#custom-container-entrypoint) to access these flags.
+A [Jib](https://github.com/GoogleContainerTools/jib) [maven extension](https://github.com/GoogleContainerTools/jib-extensions) outputs the configured `jvmFlags` into the `/app/jib-jvm-flags-file` file, allowing a [custom entrypoint](https://github.com/GoogleContainerTools/jib/tree/master/jib-maven-plugin#custom-container-entrypoint) to access these flags.
 
-When a custom entrypoint is used, Jib ignores the `jvmFlags` settings. This plugin allows the configured `jvmFlags` to still be accessed even in scenarios where a custom entrypoint is in use. 
+When a custom entrypoint is used, Jib ignores the `jvmFlags` settings. This extension ensures that the configured `jvmFlags` are accessible even in such scenarios:
 
-For example:
+- For Java 11+:
+ ```sh
+ java @/app/jib-jvm-flags-file -cp @/app/jib-classpath-file @/app/jib-main-class-file
+ ```
+- With shell:
+ ```sh
+ java $(cat /app/jib-jvm-flags-file) -cp $(cat /app/jib-classpath-file) $(cat /app/jib-main-class-file)
+ ```
 
-- (Java 11+) `java @/app/jib-jvm-flags-file -cp @/app/jib-classpath-file @/app/jib-main-class-file`
-- (with shell) `java $(cat /app/jib-jvm-flags-file) -cp $(cat /app/jib-classpath-file) $(cat /app/jib-main-class-file)`
-
-> Requires Java 11 or newer
+> **Note:** Requires Java 11 or newer
 
 ## Usage
 
+To use the Jib JVM Flags extension in your project, configure the `jib-maven-plugin` as follows:
+
 ```xml
 <plugin>
  <groupId>com.google.cloud.tools</groupId>
  <artifactId>jib-maven-plugin</artifactId>
  <version>${jib-maven-plugin.version}</version>
  <configuration>
- <container>
- <jvmFlags>
- <jvmFlag>-XshowSettings:vm</jvmFlag>
- <jvmFlag>-Xdebug</jvmFlag>
- </jvmFlags>
- <entrypoint>java,@/app/jib-jvm-flags-file,-cp,@/app/jib-classpath-file,@/app/jib-main-class-file</entrypoint>
- </container>
  <pluginExtensions>
  <pluginExtension>
  <implementation>tw.com.softleader.cloud.tools.jib.maven.JvmFlagsExtension</implementation>
@@ -47,8 +46,72 @@ For example:
 </plugin>
 ```
 
+### Customizing Entrypoint with Java Command
+
+To customize the entrypoint using a direct Java command, for example:
+
+```xml
+<configuration>
+ <container>
+ <jvmFlags>
+ <jvmFlag>-XshowSettings:vm</jvmFlag>
+ <jvmFlag>-Xdebug</jvmFlag>
+ </jvmFlags>
+ <entrypoint>java,@/app/jib-jvm-flags-file,-cp,@/app/jib-classpath-file,@/app/jib-main-class-file</entrypoint>
+ </container>
+ <pluginExtensions>
+ <pluginExtension>
+ <implementation>tw.com.softleader.cloud.tools.jib.maven.JvmFlagsExtension</implementation>
+ </pluginExtension>
+ </pluginExtensions>
+</configuration>
+```
+
+### Customizing Entrypoint Using a Shell Script
+
+You can also use a shell script to launch your app:
+
+```sh
+#!/bin/bash
+set -e
+
+# Perform any necessary steps before starting the JVM, such as calculating and setting JVM options
+export JAVA_TOOL_OPTIONS="-Xmx1g"
+
+exec java $(cat /app/jib-jvm-flags-file) -cp $(cat /app/jib-classpath-file) $(cat /app/jib-main-class-file) "$@"
+```
+
+And then configure the plugin to use this script:
+
+```xml
+<configuration>
+ <container>
+ <jvmFlags>
+ <jvmFlag>-XshowSettings:vm</jvmFlag>
+ <jvmFlag>-Xdebug</jvmFlag>
+ </jvmFlags>
+ <entrypoint>sh,/entrypoint.sh</entrypoint>
+ </container>
+ <extraDirectories>
+ <paths>
+ <path>
+ <from>.</from>
+ <includes>entrypoint.sh</includes>
+ </path>
+ </paths>
+ </extraDirectories>
+ <pluginExtensions>
+ <pluginExtension>
+ <implementation>tw.com.softleader.cloud.tools.jib.maven.JvmFlagsExtension</implementation>
+ </pluginExtension>
+ </pluginExtensions>
+</configuration>
+```
+
 ### Extension Properties 
 
+You can further customize the extension with the following properties:
+
 ```xml
 <pluginExtension>
  <implementation>tw.com.softleader.cloud.tools.jib.maven.JvmFlagsExtension</implementation>