# This patch file was generated by NetBeans IDE
# Following Index: paths are relative to: /home/work/trunk-work/nb_all/core
# This patch can be applied using context Tools: Patch action on respective folder.
# It uses platform neutral UTF-8 encoding and \n newlines.
# Above lines and this line are ignored by the patching process.
Index: startup/src/org/netbeans/core/startup/layers/SystemFileSystem.java
--- /home/work/trunk-work/nb_all/core/startup/src/org/netbeans/core/startup/layers/SystemFileSystem.java Base (1.10)
+++ /home/work/trunk-work/nb_all/core/startup/src/org/netbeans/core/startup/layers/SystemFileSystem.java Locally Modified (Based On 1.10)
@@ -279,8 +279,22 @@
             user = l;
         } else {
             // use some replacement
+            String customFSClass = System.getProperty("org.netbeans.core.systemfilesystem.custom"); // NOI18N
+            if (customFSClass != null) {
+                try {
+                    Class clazz = Class.forName(customFSClass);
+                    Object instance = clazz.newInstance();
+                    user = (FileSystem)instance;
+                } catch (Exception x) {
+                    ModuleLayeredFileSystem.err.log(
+                        Level.WARNING,
+                        "Custom system file system writable layer init failed ", x); // NOI18N
             user = FileUtil.createMemoryFileSystem ();
         }
+            } else {
+                user = FileUtil.createMemoryFileSystem ();
+            }
+        }
 
         if (homeDir == null) {
             home = null;
Index: startup/test/unit/src/org/netbeans/core/startup/layers/CustomWritableSystemFileSystemTest.java
--- /home/work/trunk-work/nb_all/core/startup/test/unit/src/org/netbeans/core/startup/layers/CustomWritableSystemFileSystemTest.java No Base Revision
+++ /home/work/trunk-work/nb_all/core/startup/test/unit/src/org/netbeans/core/startup/layers/CustomWritableSystemFileSystemTest.java Locally New
@@ -0,0 +1,75 @@
+/*
+ * The contents of this file are subject to the terms of the Common Development
+ * and Distribution License (the License). You may not use this file except in
+ * compliance with the License.
+ *
+ * You can obtain a copy of the License at http://www.netbeans.org/cddl.html
+ * or http://www.netbeans.org/cddl.txt.
+ *
+ * When distributing Covered Code, include this CDDL Header Notice in each file
+ * and include the License file at http://www.netbeans.org/cddl.txt.
+ * If applicable, add the following below the CDDL Header, with the fields
+ * enclosed by brackets [] replaced by your own identifying information:
+ * "Portions Copyrighted [year] [name of copyright owner]"
+ *
+ * Portions Copyrighted 2007 Nokia Siemens Networks Oy
+ */
+package org.netbeans.core.startup.layers;
+
+import org.netbeans.junit.NbTestCase;
+import org.openide.filesystems.FileObject;
+import org.openide.filesystems.FileSystem;
+import org.openide.filesystems.Repository;
+import org.openide.util.actions.SystemAction;
+
+/**
+ * Tests whether the system property 
+ * <code>org.netbeans.core.systemfilesystem.custom</code> correctly
+ * installs a custom filesystem.
+ * 
+ * @author David Strupl
+ */
+public class CustomWritableSystemFileSystemTest extends NbTestCase {
+
+    private SystemFileSystem sfs;
+
+    public CustomWritableSystemFileSystemTest(String testName) {
+        super(testName);
+    }
+
+    protected void setUp() throws Exception {
+        System.setProperty("netbeans.user", "memory");
+        System.setProperty("org.netbeans.core.systemfilesystem.custom", PoohFileSystem.class.getName());
+        sfs = (SystemFileSystem) Repository.getDefault().getDefaultFileSystem();
+    }
+
+    public void testCustomSFSWritableLayerPresent() throws Exception {
+        FileSystem writable = sfs.createWritableOn(null);
+        assertTrue(writable instanceof ModuleLayeredFileSystem);
+        ModuleLayeredFileSystem mlf = (ModuleLayeredFileSystem) writable;
+        assertTrue(mlf.getWritableLayer() instanceof PoohFileSystem);
+    }
+
+    public static class PoohFileSystem extends FileSystem {
+
+        public String getDisplayName() {
+            return "Pooh";
+        }
+
+        public boolean isReadOnly() {
+            return false;
+        }
+
+        public FileObject getRoot() {
+            throw new UnsupportedOperationException("Not supported yet.");
+        }
+
+        public FileObject findResource(String name) {
+            throw new UnsupportedOperationException("Not supported yet.");
+        }
+
+        public SystemAction[] getActions() {
+            throw new UnsupportedOperationException("Not supported yet.");
+        }
+    }
+}
Index: arch/arch-core-launcher.xml
--- /home/work/trunk-work/nb_all/core/arch/arch-core-launcher.xml Base (1.52)
+++ /home/work/trunk-work/nb_all/core/arch/arch-core-launcher.xml Locally Modified (Based On 1.52)
@@ -567,6 +567,16 @@
                     </p>
                 </api>
             </li>
+            <li>
+                <api type="export" group="property" name="org.netbeans.core.systemfilesystem.custom" category="friend">
+                    <p>
+                        Contains class name of a class that can serve as provider of the writable layer of the
+                        system file system. The class must be a subclass of 
+                        <code>org.openide.filesystems.FileSystem</code> and have public default constructor.
+                        Morevoer the class denoted by the property must be on the classpath.
+                    </p>
+                </api>
+            </li>
         </ul>
         <p>
             There are also some options passed to the launcher (interpreted