What the published objective requires
- Order specific and general error routes
- Choose On Error Continue or On Error Propagate from owner semantics
- Map connector errors to application error types
Domain 10 of 12 · 8% of the official blueprint
Handling Errors practice lesson
Design typed error routes whose continue, propagate and mapping behavior is predictable.
The misconception to eliminate
Choosing Continue because processing should continue somewhere. The real question is whether the owning scope should be considered successful.
Practice allocation: 5 of 60 questions in our whole-question mock blueprint.
Decision rules
Retrieve these without looking before attempting the question.
Rule 1
The first matching On-Error route wins; place specific types before ANY.
Rule 2
On Error Continue handles the error and its owner completes successfully.
Rule 3
On Error Propagate executes the handler, then fails its owner and propagates upward.
Rule 4
Error Mapping converts a processor error into an application-defined type; a Try scope creates a local handling boundary.
Worked Northstar scenario
Scenario
CRM is optional for guest orders, but DB failure must fail order creation.
Reasoning
Handle CRM:CONNECTIVITY in a Try with Continue and set a guest enrichment fallback. Map DB:CONNECTIVITY to ORDER:PERSISTENCE and Propagate so the order flow fails deliberately.
Free practice question
Which handler makes its owning Try scope complete successfully?
- On Error Propagate
- On Error Continue
- Raise Error
- Error Mapping
Reveal answer and reasoning
Answer: B. Continue handles the error and supplies the event with which the owner completes successfully.
The complete program contains five guided drills for this domain, an 80% mastery gate, saved progress and a separate 60-question timed mock.
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Prove the error contract
Inject two failures and predict the owner's outcome.
- Add a Try around CRM enrichment with a typed Continue handler.
- Map DB connectivity to ORDER:PERSISTENCE.
- Add a specific Propagate route before ANY.
- Run both failures and verify which downstream processors execute.
Evidence to keep: A trace showing guest fallback continues, while persistence failure stops the flow with ORDER:PERSISTENCE.
Primary sources
Questions about this domain
How much of the MuleSoft Developer exam is Handling Errors?
Salesforce publishes a weight of 8% for this domain. In a 60-question practice allocation, that is represented here by 5 questions.
Is this Handling Errors question from the real exam?
No. It is original independent practice material written only from public exam objectives and product documentation.