Enable to customize classworlds.conf

maven-wrapper/src/main/java/org/apache/maven/wrapper/BootstrapMainStarter.java

@@ -21,6 +21,7 @@
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.net.URL;
 import java.net.URLClassLoader;
@@ -29,6 +30,7 @@
 import java.nio.file.Path;
 import java.util.Iterator;
 import java.util.Locale;
+import java.util.Properties;
 
 /**
  * Maven starter, from a provided Maven home directory.
@@ -37,22 +39,51 @@
  */
 public class BootstrapMainStarter
 {
-    public void start( String[] args, Path mavenHome )
+    public void start( String[] args, Path mavenHome, Properties properties )
         throws Exception
     {
         final Path mavenJar = findLauncherJar( mavenHome );
         URLClassLoader contextClassLoader = new URLClassLoader( new URL[] { mavenJar.toUri().toURL() },
-                                                                ClassLoader.getSystemClassLoader().getParent() );
+                ClassLoader.getSystemClassLoader().getParent() );
+
+        // can be useful to leak the classloader with some daemon mojo but generally a wrong idea so off by default
+        if ( Boolean.parseBoolean( properties.getProperty( getClass().getName() + ".leakClassloader" ) ) )
+        {
+            doStart( args, mavenHome, properties, contextClassLoader );
+            return;
+        }
+
+        try ( final URLClassLoader ref = contextClassLoader )
+        {
+            doStart( args, mavenHome, properties, contextClassLoader );
+        }
+    }
+
+    private void doStart( final String[] args, final Path mavenHome,
+                          final Properties properties,
+                          final URLClassLoader contextClassLoader )
+            throws ClassNotFoundException, NoSuchMethodException, IllegalAccessException, InvocationTargetException
+    {
         Thread.currentThread().setContextClassLoader( contextClassLoader );
         Class<?> mainClass = contextClassLoader.loadClass( "org.codehaus.plexus.classworlds.launcher.Launcher" );
 
         System.setProperty( "maven.home", mavenHome.toAbsolutePath().toString() );
-        System.setProperty( "classworlds.conf", mavenHome.resolve( "bin/m2.conf" ).toAbsolutePath().toString() );
+        System.setProperty( "classworlds.conf", getClassworldsConf( properties, mavenHome ) );
 
         Method mainMethod = mainClass.getMethod( "main", String[].class );
         mainMethod.invoke( null, new Object[] { args } );
     }
 
+    private String getClassworldsConf( Properties properties, Path mavenHome )
+    {
+        final String override = properties.getProperty( "classworlds.conf" );
+        if ( override != null )
+        {
+            return override;
+        }
+        return mavenHome.resolve( "bin/m2.conf" ).toAbsolutePath().toString();
+    }
+
     private Path findLauncherJar( Path mavenHome )
         throws IOException
     {

maven-wrapper/src/main/java/org/apache/maven/wrapper/WrapperExecutor.java

@@ -177,7 +177,7 @@ public void execute( String[] args, Installer install, BootstrapMainStarter boot
         throws Exception
     {
         Path mavenHome = install.createDist( config );
-        bootstrapMainStarter.start( args, mavenHome );
+        bootstrapMainStarter.start( args, mavenHome, properties );
     }
 
     private String getProperty( String propertyName )

maven-wrapper/src/test/java/org/apache/maven/wrapper/WrapperExecutorTest.java

@@ -138,9 +138,13 @@ public void executeInstallAndLaunch()
   {
     WrapperExecutor wrapper = WrapperExecutor.forProjectDirectory( propertiesFile );
 
-    wrapper.execute( new String[] { "arg" }, install, start );
+    final String[] args = { "arg" };
+    wrapper.execute( args, install, start );
     verify( install ).createDist( Mockito.any( WrapperConfiguration.class ) );
-    verify( start ).start( new String[] { "arg" }, mockInstallDir );
+    verify( start ).start(
+            Mockito.eq( args ),
+            Mockito.eq( mockInstallDir ),
+            Mockito.any( Properties.class ) );
   }
 
   @Test( )