USD rent = 2000
EUR salary = 6000.53
USD disposableIncome = salary - rent
Then:
disposableIncome.toDecimal()
disposableIncome.toInteger()
disposableIncome.toString()
USD interest = disposableIncome.compoundInterest(startDate, endDate, apy)
USD tip = billTotal.tip(percentage)
USD and EUR would inherit from Money
Not sure how to implement it, might be a JVM magic thing.