udunits/src/main/java/ucar/units/UnitDBImpl.java
public final void addAlias(final String alias, final String name,
			final String symbol, final String plural)
			throws NoSuchUnitException, UnitExistsException {
		addAlias(UnitID.newUnitID(alias, plural, symbol), name);
	}
public final void addAlias(final String alias, final String name,
			final String symbol, final String plural)
			throws NoSuchUnitException, UnitExistsException {
		addAlias(UnitID.newUnitID(alias, plural, symbol), name);
	}
Adds an alias for a unit already in the database.

@param alias
The alias to be added to the database. May be null.
@param name
The name of the unit to have an alias added to the database.
@param symbol
The symbol to be added. May be null.
@param plural
The plural form of the alias. If <code>null
</code>, then regular
plural-forming rules are followed.
@throws NoSuchUnitException
The unit is not in the database.
@throws UnitExistsException
Another unit with the same alias is already in the database.