legacy/src/main/java/ucar/nc2/dt/trajectory/TrajectoryObsDatasetImpl.java
public boolean syncExtend() {
        if ( !this.netcdfDataset.hasUnlimitedDimension()) {
            return false;
        }
        try {
            if ( !this.netcdfDataset.syncExtend()) {
                return false;
            }
        } catch (IOException e) {
            return false;
        }

        // Update number of points in this TrajectoryObsDataset and in the child TrajectoryObsDatatype.
        int newNumPoints = this.trajectoryDim.getLength();
        if (this.trajectoryNumPoint >= newNumPoints) {
            return false;
        }
        this.trajectoryNumPoint = newNumPoints;
        ((Trajectory) this.trajectory).setNumPoints(
            this.trajectoryNumPoint);

        // Update end date in this TrajectoryObsDataset and in the child TrajectoryObsDatatype.
        try {
            endDate = trajectory.getTime(trajectoryNumPoint - 1);
        } catch (IOException e) {
            return false;
        }
        ((Trajectory) trajectory).setEndDate(endDate);

        return true;
    }
public boolean syncExtend() {
        if ( !this.netcdfDataset.hasUnlimitedDimension()) {
            return false;
        }
        try {
            if ( !this.netcdfDataset.syncExtend()) {
                return false;
            }
        } catch (IOException e) {
            return false;
        }

        // Update number of points in this TrajectoryObsDataset and in the child TrajectoryObsDatatype.
        int newNumPoints = this.trajectoryDim.getLength();
        if (this.trajectoryNumPoint >= newNumPoints) {
            return false;
        }
        this.trajectoryNumPoint = newNumPoints;
        ((Trajectory) this.trajectory).setNumPoints(
            this.trajectoryNumPoint);

        // Update end date in this TrajectoryObsDataset and in the child TrajectoryObsDatatype.
        try {
            endDate = trajectory.getTime(trajectoryNumPoint - 1);
        } catch (IOException e) {
            return false;
        }
        ((Trajectory) trajectory).setEndDate(endDate);

        return true;
    }
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