Observations

https://groups.google.com/forum/?fromgroups=#!topic/scala-user/nC263xUiaQo

The same dumb stupid Java where you can only pass a final into an internal class...

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List<Integer> ints = new ArrayList<>(); 
ints.add(1); 
ints.add(2); 
ints.add(3); 

int sum = 0; 
ints.forEach(i -> {sum += i;}); 

The compiler error is: "value used in lambda expression should be effectively final". I got some bad suspicion and tried whether this compiles:

int sumArray[] = new int[] { 0 }; 
ints.forEach(i -> {sumArray[0] += i;}); 

This did compile.
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