Here you can find the source of toZonedDateTime(Object cell)
public static ZonedDateTime toZonedDateTime(Object cell)
//package com.java2s; //License from project: Open Source License import java.time.Instant; import java.time.ZoneId; import java.time.ZonedDateTime; public class Main { public static ZonedDateTime toZonedDateTime(Object cell) { return ZonedDateTime.ofInstant(Instant.ofEpochMilli(toLong(cell)), ZoneId.systemDefault()); }// www . j a va2 s .c om public static Long toLong(Object cell) { if (cell instanceof Long) { return ((Long) cell); } else if (cell instanceof Integer) { return new Long((Integer) cell); } else if (cell instanceof String) { return Double.valueOf((String) cell).longValue(); } else { return null; } } }