Are you just using ArrayList whenever you need to group data?What are the specific scenarios where Set or Map are the correct ...

map.put("ソート優先1",Integer.toString((int)(Math.random() * 10 + 1))); map.put("ソート優先2",Integer.toString(i)); al.add(map); 上記の状態でalをmap ...

ArrayList is an heterogeneous collection of objects where each object can be indexed individually. While writing an application there could be some scenarios where we have ArrayList object filled with ...