# Shared Mule libraries and configuration

*MuleSoft Developer II Study Guide · Implement maintainable and modular Mule applications and their Maven builds · Last updated November 7, 2026 · https://www.certifyforce.com/study-guide/mulesoft-developer-ii/implement-maintainable-and-modular-mule-applications-and-their-maven-builds/shared-mule-libraries-and-configuration*

Package and consume reusable Mule modules, define XML module inputs and identity, and keep public operations and internal reuse boundaries explicit.

- Certification: Salesforce MuleSoft Developer II
- Exam section: Implement maintainable and modular Mule applications and their Maven builds
- Study guide: https://www.certifyforce.com/study-guide/mulesoft-developer-ii

**Official exam objective:**

> Encapsulate common Mule application functionality in libraries.

## What the exam expects

- Package reusable behaviour as a module with an explicit interface.
- Consume modules through Maven and distinguish module dependencies from application class loading.
- Configure XML module names, inputs, errors and reusable operation boundaries.
- Keep the module's public interface small and predictable.

A **module** adds reusable Mule components; a **property** configures the module; a **parameter** supplies an operation call; a **namespace** identifies its XML vocabulary; a **classifier** distinguishes Maven artifact usage. The SDK rules below are documented in the February 2024 primary sources, matching the exam's Spring 2024 context ([SDK overview](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/index.adoc)).

## Key facts

| Fact | Detail | Source |
|---|---|---|
| Module consumption | Application Maven coordinates include `mule-plugin`. | [Studio](https://docs.mulesoft.com/studio/add-custom-modules-in-studio-to) |
| Extension API | SDK modules avoid direct runtime-internal dependencies. | [SDK](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/index.adoc) |
| XML composition | Existing processors form the operation body. | [XML SDK](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/xml-sdk.adoc) |
| Resource identity | A custom prefix requires a matching resource folder. | [Prefix](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/xml-sdk.adoc) |
| Default namespace | Uses the module prefix when no namespace is explicit. | [Namespace](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/xml-sdk.adoc) |
| Requiredness | AUTO with a default is optional; REQUIRED cannot have a default. | [Inputs](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/xml-sdk.adoc) |
| Configuration | Optional properties do not remove the explicit configuration. | [Configuration](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/xml-sdk.adoc) |
| Java helper | `@Ignore` excludes a public helper from operation discovery. | [Operations](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/operations.adoc) |

## Check yourself

- Why must a review follow calls through several XML operations?
- When a business input is named `config-ref`, what interface correction is needed?
- Why use kebab-case consistently for XML SDK operation and parameter names?

## Sources

- [Add Custom Modules to Your Project](https://docs.mulesoft.com/studio/add-custom-modules-in-studio-to)
- [Mule SDK overview, February 2024](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/index.adoc)
- [XML SDK, February 2024](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/xml-sdk.adoc)
- [Operations, February 2024](https://raw.githubusercontent.com/mulesoft/docs-mule-sdk/9b03c9bd9670c1504352277299469a98f5cc6363/modules/ROOT/pages/operations.adoc)
- [Publishing Assets Using Maven](https://docs.mulesoft.com/exchange/to-publish-assets-maven)
- [Class-loading Isolation for Mule 4.6](https://docs.mulesoft.com/mule-runtime/4.6/about-classloading-isolation)

## About the full unit

The "Core concepts", "Exam traps" and "Worked scenario" sections of this unit, its 12 linked practice questions, and unlimited timed mock exams are included with the MuleSoft Developer II pack (USD $19): https://www.certifyforce.com/practice-exams