udunits/src/main/java/ucar/units/UnitDBImpl.java
public void add(final UnitDBImpl that) throws UnitExistsException {
		unitSet.addAll(that.unitSet);
		nameMap.putAll(that.nameMap);
		symbolMap.putAll(that.symbolMap);
	}
public void add(final UnitDBImpl that) throws UnitExistsException {
		unitSet.addAll(that.unitSet);
		nameMap.putAll(that.nameMap);
		symbolMap.putAll(that.symbolMap);
	}
Adds all the entries in another UnitDBImpl to this database.

@param that
The other UnitDBImpl.
@throws UnitExistsException
Attempt to redefine an existing entry.