public Builder mergeExecution(com.google.cloud.workflows.executions.v1.Execution value) {
      if (executionBuilder_ == null) {
        if (((bitField0_ & 0x00000002) != 0)
            && execution_ != null
            && execution_
                != com.google.cloud.workflows.executions.v1.Execution.getDefaultInstance()) {
          getExecutionBuilder().mergeFrom(value);
        } else {
          execution_ = value;
        }
      } else {
        executionBuilder_.mergeFrom(value);
      }
      if (execution_ != null) {
        bitField0_ |= 0x00000002;
        onChanged();
      }
      return this;
    }
<pre>
Required. Execution to be created.
</pre>

<code>
.google.cloud.workflows.executions.v1.Execution execution = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-workflow-executions/proto-google-cloud-workflow-executions-v1/src/main/java/com/google/cloud/workflows/executions/v1/CreateExecutionRequest.java