diff --git a/packages/plugin-ext-vscode/src/browser/plugin-vscode-commands-contribution.ts b/packages/plugin-ext-vscode/src/browser/plugin-vscode-commands-contribution.ts
index b4295876bf244..e7837a89c56c5 100644
--- a/packages/plugin-ext-vscode/src/browser/plugin-vscode-commands-contribution.ts
+++ b/packages/plugin-ext-vscode/src/browser/plugin-vscode-commands-contribution.ts
@@ -31,7 +31,7 @@ import TheiaURI from '@theia/core/lib/common/uri';
 import { EditorManager } from '@theia/editor/lib/browser';
 import { TextDocumentShowOptions } from '@theia/plugin-ext/lib/common/plugin-api-rpc-model';
 import { DocumentsMainImpl } from '@theia/plugin-ext/lib/main/browser/documents-main';
-import { createUntitledResource } from '@theia/plugin-ext/lib/main/browser/editor/untitled-resource';
+import { createUntitledURI } from '@theia/plugin-ext/lib/main/browser/editor/untitled-resource';
 import { fromViewColumn, toDocumentSymbol } from '@theia/plugin-ext/lib/plugin/type-converters';
 import { ViewColumn } from '@theia/plugin-ext/lib/plugin/types-impl';
 import { WorkspaceCommands } from '@theia/workspace/lib/browser';
@@ -140,7 +140,7 @@ export class PluginVscodeCommandsContribution implements CommandContribution {
          * and apply actions only to them
          */
         commands.registerCommand({ id: 'workbench.action.files.newUntitledFile' }, {
-            execute: () => open(this.openerService, createUntitledResource().uri)
+            execute: () => open(this.openerService, createUntitledURI())
         });
         commands.registerCommand({ id: 'workbench.action.files.openFile' }, {
             execute: () => commands.executeCommand(WorkspaceCommands.OPEN_FILE.id)
diff --git a/packages/plugin-ext/src/main/browser/documents-main.ts b/packages/plugin-ext/src/main/browser/documents-main.ts
index 5d1218ae1908a..0601c55d5cc73 100644
--- a/packages/plugin-ext/src/main/browser/documents-main.ts
+++ b/packages/plugin-ext/src/main/browser/documents-main.ts
@@ -20,7 +20,7 @@ import { DisposableCollection, Disposable } from '@theia/core';
 import { MonacoEditorModel } from '@theia/monaco/lib/browser/monaco-editor-model';
 import { RPCProtocol } from '../../common/rpc-protocol';
 import { EditorModelService } from './text-editor-model-service';
-import { createUntitledResource } from './editor/untitled-resource';
+import { UntitledResourceResolver } from './editor/untitled-resource';
 import { EditorManager, EditorOpenerOptions } from '@theia/editor/lib/browser';
 import URI from '@theia/core/lib/common/uri';
 import CodeURI from 'vscode-uri';
@@ -94,7 +94,8 @@ export class DocumentsMainImpl implements DocumentsMain, Disposable {
         rpc: RPCProtocol,
         private editorManager: EditorManager,
         private openerService: OpenerService,
-        private shell: ApplicationShell
+        private shell: ApplicationShell,
+        private untitledResourceResolver: UntitledResourceResolver
     ) {
         this.proxy = rpc.getProxy(MAIN_RPC_CONTEXT.DOCUMENTS_EXT);
 
@@ -169,7 +170,7 @@ export class DocumentsMainImpl implements DocumentsMain, Disposable {
     async $tryCreateDocument(options?: { language?: string; content?: string; }): Promise<UriComponents> {
         const language = options && options.language;
         const content = options && options.content;
-        const resource = createUntitledResource(content, language);
+        const resource = await this.untitledResourceResolver.createUntitledResource(content, language);
         return monaco.Uri.parse(resource.uri.toString());
     }
 
diff --git a/packages/plugin-ext/src/main/browser/editor/untitled-resource.ts b/packages/plugin-ext/src/main/browser/editor/untitled-resource.ts
index d68b1067925c9..da17771cb2566 100644
--- a/packages/plugin-ext/src/main/browser/editor/untitled-resource.ts
+++ b/packages/plugin-ext/src/main/browser/editor/untitled-resource.ts
@@ -14,39 +14,96 @@
  * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
  ********************************************************************************/
 
-import { ResourceResolver, Resource } from '@theia/core';
+import { injectable, inject } from 'inversify';
+import { TextDocumentContentChangeEvent } from 'vscode-languageserver-protocol';
+import { Resource, ResourceResolver } from '@theia/core';
 import URI from '@theia/core/lib/common/uri';
-import { injectable } from 'inversify';
 import { Schemes } from '../../../common/uri-components';
+import { FileResource, FileResourceResolver } from '@theia/filesystem/lib/browser';
 
-const resources = new Map<string, UntitledResource>();
 let index = 0;
+
 @injectable()
 export class UntitledResourceResolver implements ResourceResolver {
-    resolve(uri: URI): Resource | Promise<Resource> {
-        if (uri.scheme === Schemes.UNTITLED) {
-            return resources.get(uri.toString())!;
+
+    @inject(FileResourceResolver)
+    protected readonly fileResourceResolver: FileResourceResolver;
+
+    resources = new Map<string, UntitledResource>();
+
+    async resolve(uri: URI): Promise<UntitledResource> {
+        if (uri.scheme !== Schemes.UNTITLED) {
+            throw new Error('The given uri is not untitled file uri: ' + uri);
+        } else {
+            const untitledResource = this.resources.get(uri.toString());
+            if (!untitledResource) {
+                return this.createUntitledResource('', '', uri, this.fileResourceResolver);
+            } else {
+                return untitledResource;
+            }
+        }
+    }
+
+    async  createUntitledResource(content?: string, language?: string, uri?: URI, fileResourceResolver?: FileResourceResolver): Promise<UntitledResource> {
+        let extension;
+        if (language) {
+            for (const lang of monaco.languages.getLanguages()) {
+                if (lang.id === language) {
+                    if (lang.extensions) {
+                        extension = lang.extensions[0];
+                        break;
+                    }
+                }
+            }
         }
-        throw new Error(`scheme ${uri.scheme} is not '${Schemes.UNTITLED}'`);
+        return new UntitledResource(this.resources, uri ? uri : new URI().withScheme(Schemes.UNTITLED).withPath(`/Untitled-${index++}${extension ? extension : ''}`),
+            content, fileResourceResolver);
     }
 }
 
 export class UntitledResource implements Resource {
+    private fileResource?: FileResource;
 
-    constructor(public uri: URI, private content?: string) {
-        resources.set(this.uri.toString(), this);
+    constructor(private resources: Map<string, UntitledResource>, public uri: URI, private content?: string, private fileResourceResolver?: FileResourceResolver) {
+        this.resources.set(this.uri.toString(), this);
     }
 
-    readContents(options?: { encoding?: string | undefined; } | undefined): Promise<string> {
-        return Promise.resolve(this.content ? this.content : '');
+    dispose(): void {
+        this.resources.delete(this.uri.toString());
     }
 
-    dispose(): void {
-        resources.delete(this.uri.toString());
+    async readContents(options?: { encoding?: string | undefined; } | undefined): Promise<string> {
+        if (this.fileResource) {
+            return this.fileResource.readContents(options);
+        } else if (this.content) {
+            return Promise.resolve(this.content);
+        } else {
+            return '';
+        }
+    }
+
+    async saveContents(content: string, options?: { encoding?: string, overwriteEncoding?: string }): Promise<void> {
+        const that = this;
+        // The path of URI's with Untitled scheme has a prefix of: 'file:///'.
+        // When the user chosse to save the file we need to change the scheme from 'untitled' to 'file'.
+        // Need to find better way to remove the 'file:///' prefix from a URI with untitled scheme
+        const fileUri = new URI(this.uri.path.toString().replace('file:///', ''));
+        if (this.fileResourceResolver) {
+            this.fileResourceResolver.resolve(fileUri).then(resolvedFileResource => {
+                that.fileResource = resolvedFileResource;
+                that.fileResource.saveContents(content, options);
+            });
+        }
+    }
+
+    async saveContentChanges(changes: TextDocumentContentChangeEvent[], options?: { encoding?: string, overwriteEncoding?: string }): Promise<void> {
+        if (this.fileResource) {
+            this.fileResource.saveContentChanges(changes, options);
+        }
     }
 }
 
-export function createUntitledResource(content?: string, language?: string): UntitledResource {
+export function createUntitledURI(language?: string): URI {
     let extension;
     if (language) {
         for (const lang of monaco.languages.getLanguages()) {
@@ -58,5 +115,5 @@ export function createUntitledResource(content?: string, language?: string): Unt
             }
         }
     }
-    return new UntitledResource(new URI().withScheme(Schemes.UNTITLED).withPath(`/Untitled-${index++}${extension ? extension : ''}`), content);
+    return new URI().withScheme(Schemes.UNTITLED).withPath(`/Untitled-${index++}${extension ? extension : ''}`);
 }
diff --git a/packages/plugin-ext/src/main/browser/main-context.ts b/packages/plugin-ext/src/main/browser/main-context.ts
index 2392961b80dcb..bd530d76fcfe2 100644
--- a/packages/plugin-ext/src/main/browser/main-context.ts
+++ b/packages/plugin-ext/src/main/browser/main-context.ts
@@ -47,6 +47,7 @@ import { OpenerService } from '@theia/core/lib/browser/opener-service';
 import { ApplicationShell } from '@theia/core/lib/browser/shell/application-shell';
 import { MonacoBulkEditService } from '@theia/monaco/lib/browser/monaco-bulk-edit-service';
 import { MonacoEditorService } from '@theia/monaco/lib/browser/monaco-editor-service';
+import { UntitledResourceResolver } from './editor/untitled-resource';
 
 export function setUpPluginApi(rpc: RPCProtocol, container: interfaces.Container): void {
     const commandRegistryMain = new CommandRegistryMainImpl(rpc, container);
@@ -73,7 +74,8 @@ export function setUpPluginApi(rpc: RPCProtocol, container: interfaces.Container
     const editorManager = container.get(EditorManager);
     const openerService = container.get<OpenerService>(OpenerService);
     const shell = container.get(ApplicationShell);
-    const documentsMain = new DocumentsMainImpl(editorsAndDocuments, modelService, rpc, editorManager, openerService, shell);
+    const untitledResourceResolver = container.get(UntitledResourceResolver);
+    const documentsMain = new DocumentsMainImpl(editorsAndDocuments, modelService, rpc, editorManager, openerService, shell, untitledResourceResolver);
     rpc.set(PLUGIN_RPC_CONTEXT.DOCUMENTS_MAIN, documentsMain);
 
     const bulkEditService = container.get(MonacoBulkEditService);
diff --git a/packages/plugin-ext/src/plugin/documents.ts b/packages/plugin-ext/src/plugin/documents.ts
index 7eb590cfa12c9..3aa40e440af30 100644
--- a/packages/plugin-ext/src/plugin/documents.ts
+++ b/packages/plugin-ext/src/plugin/documents.ts
@@ -124,11 +124,11 @@ export class DocumentsExtImpl implements DocumentsExt {
     protected async fireTextDocumentWillSaveEvent({
         document, reason, fireEvent, accept
     }: {
-            document: theia.TextDocument,
-            reason: theia.TextDocumentSaveReason,
-            fireEvent: (e: theia.TextDocumentWillSaveEvent) => any,
-            accept: (operation: SingleEditOperation) => void
-        }): Promise<void> {
+        document: theia.TextDocument,
+        reason: theia.TextDocumentSaveReason,
+        fireEvent: (e: theia.TextDocumentWillSaveEvent) => any,
+        accept: (operation: SingleEditOperation) => void
+    }): Promise<void> {
 
         const promises: PromiseLike<TextEdit[] | any>[] = [];
         fireEvent(Object.freeze({