---
title: "Debug AppSail Services"
url: https://docs.catalyst.zoho.com/en/serverless/help/appsail/debug-appsail/
description: "Catalyst AppSail is a fully-managed platform of Catalyst Serverless that enables you to develop and deploy web services in managed runtimes of Java, Node.js, and Python, or of custom runtimes as OCI images to the cloud with ease."
last_updated: 2026-08-17T12:16:04Z
service: Serverless
type: general
---

# Debug AppSail Services

This section contains examples to debug sample AppSail services built on specific frameworks of [Catalyst-managed runtimes](https://docs.catalyst.zoho.com/en/serverless/help/appsail/catalyst-managed-runtimes/key-concepts/) on popular IDEs. Depending on the programming environment and  the framework, appropriate IDEs are used to demonstrate the steps.

## Java

### Debug a Spring MVC application in Visual Studio Code

Follow the steps provided in this section to debug and test a Java application built on the [Spring MVC framework](https://docs.spring.io/spring-framework/docs/3.2.x/spring-framework-reference/html/mvc.html) in the [Visual Studio Code](https://code.visualstudio.com/) environment. 

**Prerequisites:** A Spring MVC application created and available in VSCode

1. Open the Spring application project in your VSCode IDE.

2. Install the following extension in your VSCode: [Debugger for Java](https://marketplace.visualstudio.com/items?itemName=vscjava.vscode-java-debug). 

![appsail-debug-mvc-vscode](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-vscode-1.webp)

3. After the extension is installed, click on **Run**, then **Add Configuration...** Select **Java** from the tool bar.

![appsail-debug-mvc-vscode](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-vscode-2.webp)

This will open the `launch.json` file. 

4. Now click on **Add Configuration...** shown in the file and select the **Java: Attach to Remote Program** option.

![appsail-debug-mvc-vscode](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-vscode-3.webp)

5. Update the value of the "**hostName**" key as "**localhost**". Then update the value of the "**port**" key as "**5005**".

![appsail-debug-mvc-vscode](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-vscode-4.webp)

6. Now navigate to **Run** from the toolbar and click **Start Debugging** to debug your application.

![appsail-debug-mvc-vscode](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-vscode-5.webp)

### Debug a Spring MVC application in IntelliJ IDEA

Follow the steps provided in this section to debug and test a Java application built on the [Spring MVC framework](https://docs.spring.io/spring-framework/docs/3.2.x/spring-framework-reference/html/mvc.html) in the [IntelliJ IDEA environment](https://www.jetbrains.com/idea/).

**Prerequisites:** A Spring MVC application created and available in IntelliJ IDEA

1. Open the Spring application project in your IntelliJ IDEA.

2. Run the Spring application using the following command in the IDE's terminal:

```java
mvn spring-boot:run -Dspring-boot.run.jvmArguments="-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=5005" 
```

3. Right click on the **Run** option in the toolbar and click **Debug**.

![cli-appsail-add-4](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-idea-1.webp)

4. Now either click **Edit Configurations** and click on the **\+ ** icon to create a new configuration, or click **Add New Configuration** and click **Remote JVM Debug**.

![cli-appsail-add-4](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-idea-2.webp)

5. You can change the port number as per your requirements. In this example, we will port "**5005**". Now verify that the "**Use module classpath**" points to your Spring application, then click **Debug**.
 
 ![cli-appsail-add-4](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-idea-3.webp)

6. Verify if the Debug Console displays the following: "**Connected to the target VM, address: 'localhost:5005', transport: 'socket'**"

![cli-appsail-add-4](https://catalyst-docs-development.zohostratus.in/images/help/appsail/appsail-mvc-idea-4.webp)

> **Note:** Ensure that the "**Mute Breakpoints**" are not enabled.

7. You can now create breakpoints in your Spring application and start debugging it.