udunits/src/main/java/ucar/units/UnitDBImpl.java
public final void addAlias(final UnitID alias, final String name)
			throws NoSuchUnitException, UnitExistsException {
		final Unit unit = getByName(name);
		if (unit == null) {
			throw new NoSuchUnitException(name);
		}
		addByName(alias.getName(), unit);
		addByName(alias.getPlural(), unit);
		addBySymbol(alias.getSymbol(), unit);
	}
public final void addAlias(final UnitID alias, final String name)
			throws NoSuchUnitException, UnitExistsException {
		final Unit unit = getByName(name);
		if (unit == null) {
			throw new NoSuchUnitException(name);
		}
		addByName(alias.getName(), unit);
		addByName(alias.getPlural(), unit);
		addBySymbol(alias.getSymbol(), unit);
	}
Adds an alias for a unit already in the database.

@param alias
The alias to be added to the database.
@param name
The name of the unit to have an alias added to the database.
@throws NoSuchUnitException
The unit is not in the database.
@throws UnitExistsException
Another unit with the same alias is already in the database.