Added java home

package.json

@@ -80,7 +80,7 @@
             "properties": {
                 "frog.javaHome": {
                     "type": "string",
-                    "default": false,
+                    "default": "",
                     "description": "Set the java home to use for the runner."
                 }
             }

src/sessionmanager.ts

@@ -60,7 +60,8 @@ export class SessionManager {
         }
 
         let extPath = vscode.extensions.getExtension("todie.frog").extensionPath;
-        let javaHome = vscode.workspace.getConfiguration('frog').get("frog.javaHome", "")
+        const configuration = vscode.workspace.getConfiguration('frog')
+        const javaHome = configuration.get("javaHome", "")
         let java = "java";
         if (javaHome) {
             java = path.join(javaHome, 'bin', 'java')