private com.google.protobuf.SingleFieldBuilderV3<
              com.google.storagetransfer.v1.proto.TransferTypes.Schedule,
              com.google.storagetransfer.v1.proto.TransferTypes.Schedule.Builder,
              com.google.storagetransfer.v1.proto.TransferTypes.ScheduleOrBuilder>
          getScheduleFieldBuilder() {
        if (scheduleBuilder_ == null) {
          scheduleBuilder_ =
              new com.google.protobuf.SingleFieldBuilderV3<
                  com.google.storagetransfer.v1.proto.TransferTypes.Schedule,
                  com.google.storagetransfer.v1.proto.TransferTypes.Schedule.Builder,
                  com.google.storagetransfer.v1.proto.TransferTypes.ScheduleOrBuilder>(
                  getSchedule(), getParentForChildren(), isClean());
          schedule_ = null;
        }
        return scheduleBuilder_;
      }
<pre>
Specifies schedule for the transfer job.
This is an optional field. When the field is not set, the job never
executes a transfer, unless you invoke RunTransferJob or update the job to
have a non-empty schedule.
</pre>

<code>.google.storagetransfer.v1.Schedule schedule = 5;</code>
java-storage-transfer/proto-google-cloud-storage-transfer-v1/src/main/java/com/google/storagetransfer/v1/proto/TransferTypes.java