udunits/src/main/java/ucar/units/SI.java
public static synchronized SI instance() throws UnitSystemException {
    if (si == null) {
      try {
        si = new SI();
      } catch (final UnitException e) {
        throw new UnitSystemException("Couldn't initialize class SI", e);
      }
    }
    return si;
  }
public static synchronized SI instance() throws UnitSystemException {
    if (si == null) {
      try {
        si = new SI();
      } catch (final UnitException e) {
        throw new UnitSystemException("Couldn't initialize class SI", e);
      }
    }
    return si;
  }
public static synchronized SI instance ( ) throws UnitSystemException { if ( si == null ) { try { si = new SI ( ) ; } catch ( final UnitException e ) { throw new UnitSystemException ( "Couldn't initialize class SI" , e ) ; } } return si ; }
Returns an instance of the SI system of units.

@return An instance of the SI system of units.
@throws UnitSystemException Couldn't create an instance of the SI system of units.
Returns an instance of the SI system of units .