Update JDK_MANAGEMENT.md to reflect only-script implementation

Fix documentation to accurately describe the shell-based JDK management:

✅ Documentation Updates:
- Clarify that JDK management is only available for 'only-script' distribution type
- Remove references to removed Java classes (JdkResolver, JdkDownloader, etc.)
- Update all Maven plugin examples to include -Dtype=only-script
- Explain shell-based implementation architecture
- Add distribution type requirement to migration guide

✅ Key Changes:
- Replace Java class references with shell script implementation details
- Emphasize SDKMAN API integration via curl/wget and PowerShell
- Highlight chicken-and-egg problem solution
- Update all command examples to be accurate
- Add clear migration instructions

The documentation now accurately reflects the shell-based implementation
and makes it clear that JDK management requires the only-script distribution type.

Author: gnodet

src/site/markdown/JDK_MANAGEMENT.md

@@ -17,11 +17,11 @@
 
 # JDK Management in Maven Wrapper
 
-This document describes the enhanced JDK management capabilities added to Maven Wrapper, allowing projects to automatically download and manage JDK installations.
+This document describes the enhanced JDK management capabilities added to Maven Wrapper for the `only-script` distribution type, allowing projects to automatically download and manage JDK installations.
 
 ## Overview
 
-The Maven Wrapper now supports:
+The Maven Wrapper `only-script` distribution now supports:
 
 - 🚀 **Automatic JDK download and installation**
 - 📦 **JDK version management via maven-wrapper.properties**
@@ -31,6 +31,17 @@ The Maven Wrapper now supports:
 - ⚙️ **Environment variable configuration**
 - ↩️ **Backward compatibility with existing configurations**
 
+## Distribution Type Support
+
+**Important**: JDK management is **only available for the `only-script` distribution type**. This design choice avoids the chicken-and-egg problem where Java is needed to download Java.
+
+```bash
+# Generate wrapper with JDK management support
+mvn wrapper:wrapper -Dtype=only-script -Djdk=17 -DjdkVendor=temurin
+```
+
+The `only-script` distribution uses shell scripts (Unix) and PowerShell (Windows) to handle JDK download and installation directly, without requiring Java to be pre-installed.
+
 ## Configuration
 
 ### Basic JDK Configuration
@@ -120,20 +131,20 @@ export MAVEN_WRAPPER_TOOLCHAIN_JDK=11
 
 ## Maven Plugin Usage
 
-Use the Maven Wrapper plugin to configure JDK settings:
+Use the Maven Wrapper plugin to configure JDK settings (requires `only-script` distribution type):
 
 ```bash
-# Set JDK version via plugin
-mvn wrapper:wrapper -Djdk=17
+# Set JDK version via plugin (must specify only-script type)
+mvn wrapper:wrapper -Dtype=only-script -Djdk=17
 
 # Set JDK vendor
-mvn wrapper:wrapper -Djdk=17 -DjdkVendor=corretto
+mvn wrapper:wrapper -Dtype=only-script -Djdk=17 -DjdkVendor=corretto
 
 # Set toolchain JDK
-mvn wrapper:wrapper -Djdk=17 -DtoolchainJdk=11
+mvn wrapper:wrapper -Dtype=only-script -Djdk=17 -DtoolchainJdk=11
 
 # Use direct URL
-mvn wrapper:wrapper -DjdkUrl=https://example.com/jdk-17.tar.gz
+mvn wrapper:wrapper -Dtype=only-script -DjdkUrl=https://example.com/jdk-17.tar.gz
 ```
 
 ## Toolchains Integration
@@ -210,10 +221,10 @@ EOF
 
 ```bash
 # Use Amazon Corretto JDK 17
-mvn wrapper:wrapper -Djdk=17 -DjdkVendor=corretto
+mvn wrapper:wrapper -Dtype=only-script -Djdk=17 -DjdkVendor=corretto
 
 # Use Azul Zulu JDK 21
-mvn wrapper:wrapper -Djdk=21 -DjdkVendor=zulu
+mvn wrapper:wrapper -Dtype=only-script -Djdk=21 -DjdkVendor=zulu
 ```
 
 ## Security
@@ -262,18 +273,25 @@ The JDK management feature is fully backward compatible. Existing Maven Wrapper
 
 To migrate to automatic JDK management:
 
-1. Add `jdkVersion` to your `maven-wrapper.properties`
-2. Optionally specify `jdkVendor` (defaults to Temurin)
-3. Remove manual JDK installation steps from your build process
-4. Update documentation to reference the new automatic JDK management
+1. **Switch to `only-script` distribution type** (required for JDK management)
+2. Add `jdkVersion` to your `maven-wrapper.properties`
+3. Optionally specify `jdkVendor` (defaults to Temurin)
+4. Remove manual JDK installation steps from your build process
+5. Update documentation to reference the new automatic JDK management
+
+```bash
+# Migration command
+mvn wrapper:wrapper -Dtype=only-script -Djdk=17 -DjdkVendor=temurin
+```
 
 ## Implementation Details
 
-The JDK management feature consists of several components:
+The JDK management feature is implemented entirely in shell scripts for the `only-script` distribution type:
 
-- **JdkResolver**: Resolves JDK versions to download URLs
-- **JdkDownloader**: Downloads and installs JDKs
-- **ToolchainManager**: Manages toolchains.xml integration
-- **BinaryDownloader**: Generic binary download and extraction
+- **Shell Scripts**: `only-mvnw` (Unix/Linux/macOS) and `only-mvnw.cmd` (Windows)
+- **SDKMAN API Integration**: Direct HTTP calls using `curl`/`wget` and PowerShell
+- **Version Resolution**: Major version (17) → Latest patch version (17.0.14)
+- **Archive Extraction**: Native `tar`/`unzip` commands with cross-platform support
+- **Toolchain Integration**: Direct XML manipulation for `~/.m2/toolchains.xml`
 
-These components work together to provide a seamless JDK management experience while maintaining the simplicity and reliability of Maven Wrapper.
+This shell-based approach avoids the chicken-and-egg problem of needing Java to download Java, providing a self-contained solution that works without any Java runtime pre-installed.