import com.kenshoo.xlsx2csv.XlsxToCsvConverter;
import java.io.*;

public class Converter {
  private final static String SOURCE_FILE_PATH = "/path/example-input.xslx"
  private final static String DEST_FILE_NAME = "/path/example-result.csv"

  //building a new converter with default parameters
  private final XlsxToCsvConverter xlsxToCsvConverter = new XlsxToCsvConverter.Builder().build();

    public void function convert() {
      final FileOutputStream outputStream = new FileOutputStream(new File(DEST_FILE_NAME));
      final InputStream inputStream = new FileInputStream((SOURCE_FILE_PATH);

      xlsxToCsvConverter.convert(inputStream, outputStream);
    }
}