Anypoint Code Builder Troubleshooting - Fix the Shit That Breaks

Mule Runtime Won't Start (The Daily Special)

"Mule Home or Mule Runtimes Directory fields are misconfigured" - This error appears when VS Code can't find your Mule runtime. Here's the fix that actually works:

1. Download the runtime manually from MuleSoft Downloads. Don't trust the auto-download - it fails half the time.

2. Extract to a clean directory like /usr/local/mule/mule-enterprise-4.6.0 (macOS/Linux) or C:\mule\mule-enterprise-4.6.0 (Windows).

3. Set the runtime path in VS Code: Cmd+Shift+P

"Mule DX: Add Mule Runtime" and point it to your extracted directory.

Pro tip: Version 4.9 breaks shit that worked in 4.8. Stick with 4.6 or 4.7 if you value your sanity. Check the Java Support matrix for compatibility issues.

Memory Issues That Kill Your Flow

OutOfMemoryError during debug/run - Your Mule runtime needs more heap space. Edit your launch configuration:

{
    "name": "Debug Mule Application", 
    "vmArgs": [
        "-Xmx2048m",
        "-Xms512m", 
        "-XX:+UseG1GC"
    ]
}

For heavy DataWeave transformations, bump to -Xmx4096m. Your laptop will hate you, but at least your app won't crash. See Performance Tuning Guide for memory optimization tips.

VS Code eating all your RAM - The Java Language Server goes nuts with large projects. Add this to VS Code settings:

{
    "java.jdt.ls.vmargs": "-Xmx1G -XX:+UseG1GC",
    "mule.runtimeVMArguments": "-Xmx2048m"
}

Project Won't Compile (XML Hell)

"Failed to build project" with cryptic Maven errors usually means dependency conflicts. Check your pom.xml for version mismatches. Consult the Maven Troubleshooting Guide and MuleSoft Dependencies documentation:

<!-- Common conflict: Jackson versions -->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.13.4</version> <!-- This needs to match Mule's version -->
</dependency>

Nuclear Maven option: Delete .m2/repository/com/mulesoft and .m2/repository/org/mule folders. Let Maven re-download everything. Takes 20 minutes but fixes 90% of dependency hell. See Maven Repository Guide for repository management.

"Unable to find sample data" in DataWeave - Your sample files are in the wrong location. They need to be in src/main/resources/sample_data/, not wherever Code Builder's AI decided to put them. Check the DataWeave Testing Guide and Sample Data Best Practices.

The Debug Session That Never Ends

Debugger hangs at breakpoint - This happens when you have multiple runtime instances fighting over the same port. Kill everything:

## macOS/Linux
lsof -ti:8081,8082,1099 | xargs kill -9

## Windows PowerShell  
Get-NetTCPConnection -LocalPort 8081,8082,1099 | Stop-Process -Force

Can't connect to debugger - The debug port (1099) is blocked by firewall or another process. Change it in your launch config:

{
    "debuggerPort": 6666,
    "enableDebugger": true
}

Application starts but HTTP listener fails - Port 8081 is taken. Either kill whatever's using it or change your HTTP listener to port 8090. Don't use 8080 - every Java app uses that shit. See HTTP Connector Configuration and Network Troubleshooting for port management tips.

When Einstein AI Goes Stupid

Einstein generates flows that compile but don't work - The AI loves creating transforms that look correct but fail with real data. It doesn't understand null handling, array edge cases, or complex business logic.

Reality check: If your flow has more than 3 steps, write it manually. Einstein is good for basic "connect A to B" scenarios, terrible for anything involving conditional logic or error handling. See the Einstein AI limitations and AI best practices guide.

"AI services temporarily unavailable" - This happens when Salesforce's AI services are overloaded or your region doesn't have AI enabled yet. Check your org settings - Einstein AI only works in US, EU, Canada, and Japan.

DataWeave Transform Hell

"Cannot coerce Object to Array" - The most common DataWeave error. Your source data is an object, but your transform expects an array. Fix with conditional logic:

%dw 2.0
output application/json
---
// Handle both single object and array inputs
if (payload is Array) payload
else [payload]

"Unable to find sample data" - Code Builder can't find your test JSON files. They need to be in src/main/resources/sample_data/ with exact filenames matching your DataWeave references. See DataWeave sample data documentation and DataWeave testing framework.

AI-generated DataWeave fails in production - Einstein doesn't understand production data patterns. It generates transforms based on perfect sample data, then breaks when it encounters:

• Null values in required fields
• Different array lengths than expected
• Mixed data types in the same field
• Unicode characters or special formatting

Always add null checks to any AI-generated DataWeave:

%dw 2.0
output application/json
---
{
    name: payload.firstName default "",
    email: payload.contacts.email[0] default null,
    phone: if (payload.contacts.phone != null) payload.contacts.phone[0] else null
}

Design Center API Issues

"Project loading failed" - The Design Center integration is flaky. Try these in order:

1. Refresh the browser page (for Cloud IDE)
2. Restart VS Code (for Desktop IDE)
3. Clear authentication and log in again
4. Use the web-based Design Center instead

API spec validation errors - Code Builder's RAML validator is stricter than the web version. Common issues:

• Missing baseUri in RAML specs
• Inconsistent indentation (use 2 spaces, not tabs)
• Referenced types not properly defined in separate files

Check the RAML specification and OpenAPI 3.0 guide for proper syntax.

"Cannot publish to Exchange" - Your API spec has validation errors that prevent publishing. Run mvn clean validate locally to see the actual error messages - the IDE hides the useful details. See Publishing to Exchange and Exchange Asset Guidelines.

Git and Source Control Disasters

"Git authentication failed" - VS Code's Git integration conflicts with Code Builder's authentication. Use a personal access token instead of password authentication.

Merge conflicts in XML files - Mule's XML format creates nightmare merge conflicts. Use XMLStarlet or configure Git to treat .xml files as binary:

## In your .gitattributes file
*.xml merge=ours

Project corruption after Git operations - Sometimes Git operations break the Mule project structure. Nuclear option: re-import the project using "File → Import → Anypoint Studio Project" and point it to your Git workspace. See Git Best Practices and MuleSoft Project Structure.