currencyExchangeHelper = CurrencyExchangeHelper::newExchangeDate(currentLedgerRecId, this.TransDate);
What does this line of syntax mean ?
It will create an object of the class, by using that static constructor(newExchangeDate).
By doing so, you can access its members (methods).
Syntactically, it calls a static method with two arguments and assign the result to a variable.
Kranthi already explained the purpose of the call.
I would just be careful not calling it a static constructor; that’s something else. newExchangeDate() is a method.