Throw exception in optional in Java8

Question

There is a method get(sql) (I can not modify it). This method returns MyObjects and it has to be in try catch block because JqlParseException is possible there. My code is:

String sql = something; try{    MyObject object = get(sql); } catch(JqlParseException e){    e.printStackTrace(); } catch(RuntimeException e){    e.printStackTrace(); } 

I want to remove try catch and use Optional class, I tried:

MyObject object = Optional.ofNullable(get(sql)).orElseThrow(RuntimeException::new); 

but IDE force there try catch too. And for:

MyObject object = Optional.ofNullable(get(sql)).orElseThrow(JqlParseException::new)); 

is an error (in IDE) The type JqlParseException does not define JqlParseException() that is applicable. Is there any way to avoid try catch blocks and use optional?

Answer 1

Optional is not intended for the purpose of dealing with exceptions, it was intended to deal with potential nulls without breaking the flow of your program. For example:

 myOptional.map(Integer::parseInt).orElseThrow(() -> new RuntimeException("No data!"); 

This will automatically skip the map step if the optional was empty and go right to the throw step -- a nice unbroken program flow.

When you write:

 myOptionalValue.orElseThrow(() -> new RuntimeException("Unavailable")); 

... what you are really saying is: Return my optional value, but throw an exception if it is not available.

What you seem to want is a way to create an optional (that instantly catches the exception) and will rethrow that exception when you try using the optional.