Camunda 7 Form Submit Error – Expression Returns Non-Boolean (Root Cause & Fix)
In Camunda 7 , form submissions often fail with a confusing runtime error: ❌ Cannot submit task form Condition expression returns non-Boolean: result has class java.lang.String and not java.lang.Boolean This issue is very common when using embedded forms, task forms, gateways, or conditional flows . This blog explains why it happens , how to identify the root cause , and how to fix it correctly . 1️⃣ What This Error Actually Means Camunda expects Boolean ( true / false ) values in: Sequence flow conditions Gateway conditions Conditional events Form field validations (indirectly) But instead, the expression is returning: A String ( "true" , "false" , "yes" , "no" ) Or a non-Boolean object (e.g. Integer , Long , null ) ➡️ Result: Form submission fails 2️⃣ Most Common Root Causes đź”´ Root Cause 1: Form Field Type Is String (Not Boolean) In Camunda forms, values are Strings by default . Example: < input type = "radio" cam-variable...