Hashmap with Streams in Java 8 Streams to collect value of Map

Question

Let consider a hashmap

Map id1 = new HashMap();

I inserted some values into both hashmap.

For

Answer 1

Maybe the sample is oversimplified, but you don't need the Java stream API here. Just use the Map directly.

 List list1 = id1.get(1); // this will return the list from your map