// "Replace with collect" "true" import java.util.ArrayList; import java.util.List; import java.util.Map; public class Main { public List test(Map> map) { List result = new ArrayList<>(); for(Map.Entry> entry : map.entrySet()) { if(entry.getKey().isEmpty()) continue; List list = entry.getValue(); if(list == null) continue; for(String str : list) { String trimmed = str.trim(); if(trimmed.isEmpty()) continue; result.add(trimmed); } } return result; } }