When to avoid functional programming?

[Adrian Grabowski]

When should we not consider using lambdas and streams while writing new code or refactoring?

[Venkat Subramaniam]

A few situations:

The code has a lot of unavoidable side-effects that can't really be pushed to outside the functional pipelines.
The code would turn complex due to excessive exception handling and loose clarity or cohesiveness.

It is a good quality to be willing to evaluate, by way of prototyping, if imperative or functional style is a better choice for a particular problem on hand.
I often say that we're not in a competition where we are required to program in a particular style. We should be willing to pick what makes sense for a given situation.

[Burk Hufnagel]

Venkat,
This sounds like something we'll get better at as we get more experience with using Lambdas and the FP style of coding.

[Venkat Subramaniam]

I agree, Burk, with experience and willingness to shift between the paradigms as needed helps.