> For the complete documentation index, see [llms.txt](https://docs.wproofreader.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.wproofreader.com/v6.11.0/deployment/configuration/grammar-check-engine-setup/enabling-grammar-engine.md).

# Enabling grammar engine

The grammar engine [requires](/v6.11.0/deployment/installation-requirements/software-requirements.md) Java **17 or higher**.

If `PathToJavaVirtualMachine` is empty, AppServer tries to auto-detect the JVM.

If needed, set the JVM path manually in `AppServerX.xml`.

You can also configure the grammar engine during installation:

* [Install on Windows with IIS](/v6.11.0/deployment/installation/windows/install-on-windows-with-iis.md)
* [Install on Linux with NGINX](/v6.11.0/deployment/installation/linux/install-on-linux-with-nginx.md)
* [Automated install on Linux](/v6.11.0/deployment/installation/linux/automated-installation-on-linux.md) (path\_to\_jvm)

{% stepper %}
{% step %}

### Install Java 17+

Install **JRE 17+** or **JDK 17+** on the same server.

The grammar engine runs inside a Java Virtual Machine (JVM).
{% endstep %}

{% step %}

### Update AppServerX.xml

Locate `AppServerX.xml` in your WebSpellChecker installation directory:

`<WebSpellChecker_Installation_Path>/AppServer/AppServerX.xml`

Find these tags:

* [`PathToJavaVirtualMachine`](/v6.11.0/deployment/configuration/application-server/appserver-parameters.md#draft-appserverparameters-pathtojavavirtualmachine)
* `JVMMaxMemorySizeMb` (see [Configure JVM maximum heap size](/v6.11.0/deployment/configuration/grammar-check-engine-setup/configure-jvm-maximum-heap-size.md))

Update the values as needed:

```xml
<!-- Java 17 or higher is required to use LanguageTool grammar engine. In case of empty tag AppServer tries to detect path to JVM library automatically. -->
<!-- You can put your path to JVM library here. Path example for Linux: '/usr/lib/jvm/java-17-openjdk-amd64/lib/server/libjvm.so'. -->
<!-- Path example for Windows: 'C:/Program Files/Java/jdk-17/bin/server/jvm.dll' -->
<PathToJavaVirtualMachine></PathToJavaVirtualMachine>
<!-- Put maximum heap size restriction in megabytes for LanguageTool in Java Virtual Machine. -->
<JVMMaxMemorySizeMb>2048</JVMMaxMemorySizeMb>
```

{% endstep %}

{% step %}

### Restart AppServer

Restart AppServer to apply changes in `AppServerX.xml`.

To restart: [stop](https://docs.wproofreader.com/v6.11.0/deployment/configuration/grammar-check-engine-setup/pages/IA2KNQLXDh85TwDivL4y#mainappservercommands-stopappserverwindowslinux2.stopappserver) the application, then [start](https://docs.wproofreader.com/v6.11.0/deployment/configuration/grammar-check-engine-setup/pages/IA2KNQLXDh85TwDivL4y#mainappservercommands-startappserverwindowslinux1.startappserver) it again.

Use [Main AppServer commands](/v6.11.0/deployment/configuration/application-server/main-appserver-commands.md).
{% endstep %}

{% step %}

### Verify operability

The status should show **"active": true** for the grammar engine.

1. Check the [status](/v6.11.0/api-reference/auxiliary-api-commands/status-api.md):

```json
{
    "SpellCheckEngine": {
        "active": true
    },
    "GrammarCheckEngine": {
        "active": true
    },
    "EnglishAIModel": {
        "active": true
    },
    "GermanAIModel": {
        "active": true
    },
    "SpanishAIModel": {
        "active": true
    },
    "EnglishAutocomplete": {
        "active": true,
    }
}
```

2. Open the demo sample pages:

`http(s)://<your_host_name>:<port>/<virtual_directory>/samples`

3. Check `AppServer/Logs` (for example, `Child-0.log`, `Child-1.log`).

You’ll see this error if AppServer can’t load the JVM:

```
MM/DD/YY:HH:MM:50.821	#18794:0	Subsystem_General	Error	Failed to load Java Virtual Machine (JVM). At least Java 17 is required to use the algorithmic grammar engine. You can specify a path to JVM in AppServerX.xml in the PathToJavaVirtualMachine tag.
```

{% endstep %}
{% endstepper %}

### Related topics

* [AppServer parameters](/v6.11.0/deployment/configuration/application-server/appserver-parameters.md)
* [Configure JVM maximum heap size](/v6.11.0/deployment/configuration/grammar-check-engine-setup/configure-jvm-maximum-heap-size.md)
* [Install on Windows with IIS](/v6.11.0/deployment/installation/windows/install-on-windows-with-iis.md)
* [Install on Linux with NGINX](/v6.11.0/deployment/installation/linux/install-on-linux-with-nginx.md)
* [Automated install on Linux](/v6.11.0/deployment/installation/linux/automated-installation-on-linux.md)