public void setStateTransitionReason(String stateTransitionReason) {
        this.stateTransitionReason = stateTransitionReason;
    }
<p>
Indicates whether a user or Lambda made the last change to the event source mapping.
</p>

@param stateTransitionReason
       Indicates whether a user or Lambda made the last change to the event source mapping.
aws-java-sdk-lambda/src/main/java/com/amazonaws/services/lambda/model/EventSourceMappingConfiguration.java