Update README.md

Author: mhoffrog

README.md

@@ -55,7 +55,13 @@ For information about the latest releases, recent updates, and newly supported d
   #### Maven options
   The action has a bunch of inputs to generate maven's [settings.xml](https://maven.apache.org/settings.html) on the fly and pass the values to Apache Maven GPG Plugin as well as Apache Maven Toolchains. See [advanced usage](docs/advanced-usage.md) for more.
 
-  - `overwrite-settings`: By default action overwrites the settings.xml. In order to skip generation of file if it exists, set this to `false`.
+  - `overwrite-settings`: By default action overwrites the settings.xml and adds a toolchain entry to toolchains.xml. In order to skip generation of settings.xml and skip adding a toolchain entry to toolchains.xml if the according file exists, set this to `false`.
+
+  - `update-env-javahome`: By default action updates `env.JAVA_HOME` with the path of java installed. In order to skip update of JAVA_HOME, set this to `false`. The creation of the env variable JAVA_HOME_{{ MAJOR_VERSION }}_{{ ARCHITECTURE }} is NOT affected by this item. That will be created for any setup.
+
+  - `update-env-path`: By default action adds `<java_install_dir>/bin` to `env.PATH`. In order to skip this, set this to `false`.
+
+  - `update-toolchains-only`: If set to true, then `overwrite-settings`, `update-env-javahome` and `update-env-path` are propagated to `false` if the specific one is not explicitly configured to `true`. Only a toolchain entry will be added to toolchains.xml. Default is `false`.
 
   - `server-id`: ID of the distributionManagement repository in the pom.xml file. Default is `github`.
 
@@ -257,6 +263,8 @@ All configured Java versions are added to the PATH. The last one added to the PA
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 ```
 
+**NOTE:** An alternative option is to use multiple setup-java steps. In this case the behavior can be controlled more granular by making use of the input items `overwrite-settings`, `update-env-javahome`, `update-env-path` and `update-toolchains-only`.
+
 ### Using Maven Toolchains
 In the example above multiple JDKs are installed for the same job. The result after the last JDK is installed is a Maven Toolchains declaration containing references to all three JDKs. The values for `id`, `version`, and `vendor` of the individual Toolchain entries are the given input values for `distribution` and `java-version` (`vendor` being the combination of `${distribution}_${java-version}`) by default.