Document Java migration tool

Author: emirmx

content/en/docs/refguide/modeling/menus/view-menu/update-assistant.md

@@ -2,7 +2,7 @@
 title: "Update Assistant (Beta)"
 url: /refguide/update-assistant/
 weight: 70
-description: "Describes the Update Assistant (Beta) pane for scanning Java deprecations in Mendix Studio Pro."
+description: "Describes the Update Assistant (Beta) pane for scanning Java deprecations in Mendix Studio Pro, and the Java Migration Tool CLI for automatically applying fixes."
 ---
 
 ## Introduction
@@ -64,8 +64,129 @@ This dialog box shows the following information:
 
 The highlighted code helps you locate the deprecated call in the file and update it.
 
+## Java Migration Tool (CLI) {#java-migration-tool}
+
+The **Java Migration Tool** (`jmt`) is a command-line utility that automatically rewrites deprecated Mendix Java API calls.
+
+The tool complements the Update Assistant pane: use the pane to identify deprecations, and the CLI to apply the fixes automatically.
+
+### Installation {#jmt-installation}
+
+Download the tool from Mendix CDN: https://cdn.mendix.com/mendix-java-migration-tool/jmt-1.0.0.jar
+
+### Basic Usage {#jmt-basic-usage}
+
+Run the tool from a Command Prompt. Use the same Java version that Studio Pro uses — you can find the Java installation path in Studio Pro's preferences.
+
+If Java is on your `PATH`, call `java` directly. If not, provide the full path to the `java` executable. Similarly, either run the command from the directory where you saved `jmt-1.0.0.jar`, or specify its full path in the command.
+
+The following example rewrites all Java files in `javasource/` to the target Studio Pro version:
+
+```cmd
+"C:\Program Files\Eclipse Adoptium\jdk-21.0.5.11-hotspot\bin\java" -jar jmt-1.0.0.jar rewrite --to-version 11.11 --studio-pro "C:\Program Files\Mendix\11.11.0" --project-root "C:\Users\YourName\Mendix\MyApp"
+```
+
+Replace the paths and version number with the actual values for your installation. For all available commands and options, see [Commands](#jmt-commands) and [Options](#jmt-options).
+
+### Commands {#jmt-commands}
+
+Run the tool with `java -jar jmt-1.0.0.jar <COMMAND> [OPTIONS]`.
+
+| Command | Description |
+|---------|-------------|
+| `version` | Display the tool version |
+| `recipes` | List all available migration recipes |
+| `rewrite <PATHS>` | Rewrite Java files at the given paths (files or directories) |
+
+### Options {#jmt-options}
+
+**Global:**
+
+* `-h, --help` – show usage information
+
+**`recipes` command:**
+
+* `-o, --output <FORMAT>` – output format: `text` (default) or `json`
+
+**`rewrite` command:**
+
+* `-t, --to-version <VERSION>` – *(required)* target Studio Pro version, for example `11.2.0`
+* `-n, --dry-run` – preview changes without writing files
+* `-o, --output <FORMAT>` – output format: `text` (default) or `json`
+* `-p, --project-root <PATH>` – root of the Mendix project; enables classpath resolution via `javasource/`, `vendorlib/`, and `userlib/`
+* `-s, --studio-pro <PATH>` – Studio Pro installation directory; enables Mendix public Java API resolution via the runtime bundles
+
+{{% alert color="warning" %}}
+Using `-p` and `-s` is strongly recommended. The tool relies on type binding resolution to apply recipes correctly — for example, it only rewrites `getMember` calls when it can confirm the receiver is an `IMendixObject`. Without these options, type information may be incomplete and recipes may not apply.
+
+For the same reason, the Java code in your project must be error-free as much as possible before running the tool. Missing imports, unresolved types, or variables declared without a fully qualified type name can prevent a recipe from recognizing a valid call site.
+{{% /alert %}}
+
+### Examples {#jmt-examples}
+
+```bash
+# List available recipes
+java -jar jmt-1.0.0.jar recipes
+
+# Apply with full project context for accurate type resolution
+java -jar jmt-1.0.0.jar rewrite javasource/ -t 11.2.0 \
+  -p /path/to/mendix-project \
+  -s "/path/to/Studio Pro 11.2.0"
+
+# Preview changes without writing (dry run)
+java -jar jmt-1.0.0.jar rewrite javasource/ -t 11.2.0 -n
+
+# Apply all applicable recipes to the javasource directory
+java -jar jmt-1.0.0.jar rewrite javasource/ -t 11.2.0
+
+# Machine-readable output for CI/CD integration
+java -jar jmt-1.0.0.jar rewrite javasource/ -t 11.2.0 -o json
+```
+
+### Output Formats {#jmt-output-formats}
+
+**Text** (default) — human-readable summary:
+
+```
+[REWRITE] Target version: 11.2.0
+Applied recipes:
+  - Replace IMendixObject.getMember(...) (available from: 10.18)
+
+Changed: javasource/myfirstmodule/actions/MyAction.java
+  Replace IMendixObject.getMember(...): 2
+
+Files processed: 1
+Files changed: 1
+Total changes: 2
+```
+
+**JSON** — machine-readable, suitable for CI/CD pipelines:
+
+```json
+{
+  "status": "success",
+  "dryRun": false,
+  "filesProcessed": 1,
+  "filesChanged": 1,
+  "totalChanges": 2,
+  "files": [
+    {
+      "file": "javasource/myfirstmodule/actions/MyAction.java",
+      "changes": [
+        {
+          "recipe": "Replace IMendixObject.getMember(IContext, String) with IMendixObject.getMember(String)",
+          "count": 2
+        }
+      ]
+    }
+  ],
+  "warnings": []
+}
+```
+
 ## Read More
 
 * [View Menu](/refguide/view-menu/)
 * [Errors Pane](/refguide/errors-pane/)
 * [Studio Pro Overview](/refguide/studio-pro-overview/)
+* [Java Programming](/refguide/java-programming/)