Java 8 forEach cannot get count in lambda expression

Question

My code is:

    int count = 0;
    contactVisits.keySet().forEach(
            key -> {
                count++; //cannot reach count here 

                //.doing my stuff......

                // ..
            }
    );

i need count in lambda, counting with "count" variable but netbeans telling me a problem like "local variables referenced from a lambda expression must be final or effectively final"

Is there a way to get index count of map in Lambda expression or getting a variable outside ?

What do you mean by index count of a Map where there's no such thing called index in a map. — Ravindra Ranwala
– Ravindra Ranwala, Commented Oct 4, 2018 at 7:42

L.dev · Accepted Answer · 2018-10-04 08:13:10Z

1

Best way is just use size() method on your map.

You may also use atomicinteger instead of int, and call getAndIncremend instead count++, however its not effective.

There is also stream().count() but i think first approach is the best.

answered Oct 4, 2018 at 8:13

L.dev

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