udunits/src/main/java/ucar/units/StandardUnitDB.java
public static synchronized StandardUnitDB instance() throws UnitDBException {
    if (instance == null) {
      try {
        instance = new StandardUnitDB();
      } catch (Exception e) {
        throw new UnitDBException("Couldn't create standard unit-database", e);
      }
    }
    return instance;
  }
public static synchronized StandardUnitDB instance() throws UnitDBException {
    if (instance == null) {
      try {
        instance = new StandardUnitDB();
      } catch (Exception e) {
        throw new UnitDBException("Couldn't create standard unit-database", e);
      }
    }
    return instance;
  }
Gets an instance of this database.

@return An instance of this database.
@throws UnitDBException The instance couldn't be created.