Java List to Map convertion

Question

I\'d like to convert a Map from List in java 8 something like this:

Map

        

Answer 1

the toMap collector receives two mappers - one for the key and one for the value. The key mapper could just return the value from the list (i.e., either name -> name like you currently have, or just use the builtin Function.Identity). The value mapper should just return the hard-coded value of 0 for any key:

namesMap = 
    names.stream().collect(Collectors.toMap(Function.identity(), name -> 0));