Change vscode-boot-java in a 'dummy' extension

It pops up a message on activation advising user to uninstall it and
install vscode-spring-boot instead.

vscode-extensions/vscode-boot-java/lib/Main.ts

@@ -1,48 +1,11 @@
 'use strict';
 
-import * as net from 'net';
-
 import * as VSCode from 'vscode';
-import * as Path from 'path';
-import * as FS from 'fs';
-import * as Net from 'net';
-import * as ChildProcess from 'child_process';
-import { LanguageClient, LanguageClientOptions, SettingMonitor, ServerOptions, StreamInfo } from 'vscode-languageclient';
-import { workspace, TextDocument } from 'vscode';
-import { Trace } from 'vscode-jsonrpc';
-
-import * as commons from 'commons-vscode';
-import { connect } from 'tls';
 
+/** Called when extension is activated */
 export function activate(context: VSCode.ExtensionContext) {
-    let options: commons.ActivatorOptions = {
-        DEBUG: false,
-        CONNECT_TO_LS: false,
-        extensionId: 'boot-java',
-        preferJdk: true,
-        launcher: (context: VSCode.ExtensionContext) => 'org.springframework.boot.loader.JarLauncher',
-        classpath: (context: VSCode.ExtensionContext, jvm: commons.JVM) => {
-            const classpath = [
-                Path.resolve(context.extensionPath, 'jars/language-server.jar')
-            ];
-            if (!jvm.isJdk()) {
-                VSCode.window.showWarningMessage('JAVA_HOME or PATH environment variable seems to point to a JRE. A JDK is required, hence Boot Hints are unavailable.');
-            }
-            const toolsJar = jvm.getToolsJar();
-            if (toolsJar) {
-                classpath.unshift(toolsJar);
-            }
-            return classpath;
-        },
-        clientOptions: {
-            documentSelector: ['java'],
-            synchronize: {
-                configurationSection: 'boot-java'
-            },
-            initializationOptions: {
-                workspaceFolders: workspace.workspaceFolders ? workspace.workspaceFolders.map(f => f.uri.toString()) : null
-            },
-        }
-    };
-    commons.activate(options, context);
+    VSCode.window.showInformationMessage(
+        "The `vscode-boot-java` extension is obsolete and no longer functional. "+
+        "Please uninstall it and install the `vscode-spring-boot` extension instead."
+    );
 }