public Builder mergeError(com.google.cloud.workflows.executions.v1beta.Execution.Error value) {
      if (errorBuilder_ == null) {
        if (((bitField0_ & 0x00000040) != 0)
            && error_ != null
            && error_
                != com.google.cloud.workflows.executions.v1beta.Execution.Error
                    .getDefaultInstance()) {
          getErrorBuilder().mergeFrom(value);
        } else {
          error_ = value;
        }
      } else {
        errorBuilder_.mergeFrom(value);
      }
      if (error_ != null) {
        bitField0_ |= 0x00000040;
        onChanged();
      }
      return this;
    }
<pre>
Output only. The error which caused the execution to finish prematurely.
The value is only present if the execution's state is `FAILED`
or `CANCELLED`.
</pre>

<code>
.google.cloud.workflows.executions.v1beta.Execution.Error error = 7 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-workflow-executions/proto-google-cloud-workflow-executions-v1beta/src/main/java/com/google/cloud/workflows/executions/v1beta/Execution.java