Java Stream Collectors.toMap value is a Set

Question

I want to use a Java Stream to run over a List of POJOs, such as the list List below, and transform it into a Map Map>

Answer 1

Also, you can use the merger function option of the Collectors.toMap function Collectors.toMap(keyMapper,valueMapper,mergeFunction) as follows:

final Map m = as.stream()
                                .collect(Collectors.toMap(
                                          x -> x.name, 
                                          x -> x.property,
                                          (property1, property2) -> property1+";"+property2);