Answer by Gergana Toncheva for How to sort List of objects by some property

public class ActiveAlarm {    public long timeStarted;    public long timeEnded;    private String name = "";    private String description = "";    private String event;    private boolean live = false;}List<ActiveAlarm> con = new ArrayList<ActiveAlarm>();Collections.sort(con , (a1, a2) -> a1.timeStarted.compareTo(a2.timeStarted));Collections.sort(con , (a1, a2) -> a1.timeEnded.compareTo(a2.timeEnded));