Perhaps all do not know that... the interface JGrassConstants holds important path pieces

Since lots of things change as time passes by, the GRASS location and mapset path pieces are hold in a facility interface called JGrassConstants.
So instead of writing WIND to define the active region file, you can (or better should, or better must) use JGrassConstans.WIND

Here some of the most important parts:

/** folder of the JGrass database structure */
  public final String PERMANENT_MAPSET = "PERMANENT";

  /** folder of the JGrass database structure */
  public final String DEFAULT_WIND = "DEFAULT_WIND";

  /** folder of the JGrass database structure */
  public final String PROJ_INFO = "PROJ_INFO";

  /** folder of the JGrass database structure */
  public final String PROJ_WKT = "PROJ_INFO.WKT";

  /** folder of the JGrass database structure */
  public final String PROJ_UNITS = "PROJ_UNITS";

  /** folder of the JGrass database structure */
  public final String WIND = "WIND";

  /** folder of the JGrass database structure */
  public final String MYNAME = "MYNAME";

  /** folder of the JGrass database structure */
  public final String FCELL = "fcell";

  /** folder of the JGrass database structure */
  public final String CELL = "cell";

  /** folder of the JGrass database structure */
  public final String CATS = "cats";

  /** folder of the JGrass database structure */
  public final String HIST = "hist";

  /** folder of the JGrass database structure */
  public final String CELLHD = "cellhd";

  /** folder of the JGrass database structure */
  public final String COLR = "colr";

  /** folder of the JGrass database structure */
  public final String CELL_MISC = "cell_misc";

  /** folder of the JGrass database structure */
  public final String CELLMISC_FORMAT = "f_format";

  /** folder of the JGrass database structure */
  public final String CELLMISC_QUANT = "f_quant";

  /** folder of the JGrass database structure */
  public final String CELLMISC_RANGE = "f_range";

  /** folder of the JGrass database structure */
  public final String CELLMISC_NULL = "null";