udunits/src/main/java/ucar/units/UnitSystemManager.java
public static synchronized void setInstance(final UnitSystem instance)
			throws UnitSystemException {
		if (instance != null) {
			throw new UnitSystemException("Unit system already used");
		}
		UnitSystemManager.instance = instance;
	}
public static synchronized void setInstance(final UnitSystem instance)
			throws UnitSystemException {
		if (instance != null) {
			throw new UnitSystemException("Unit system already used");
		}
		UnitSystemManager.instance = instance;
	}
public static synchronized void setInstance ( final UnitSystem instance ) throws UnitSystemException { if ( instance != null ) { throw new UnitSystemException ( "Unit system already used" ) ; } UnitSystemManager . instance = instance ; }
Sets the system of units. This must be called before any call to
<code>instance()</code>.

@param instance
The system of units.
@throws UnitSystemException
<code>instance()</code> was called earlier.
Sets the system of units . This must be called before any call to <code > instance () < / code > .