The time zone map library provides a convenient way of determining the relevant time zone for any location on earth. The map hails from timezone-boundary-builder, which is derived from OpenStreetMap data. The idea, and the overall design pattern, comes from Timeshape.

This library seeks to:

• Present a clean and simple API.
• Be as fast and small as possible, with minimal dependencies, lending itself well to mobile applications.
• Expose the region covered by each time zone to enable custom logic.
• Handle overlapping time zones deterministically.
• Conserve memory by not loading regions that are unnecessary.
• Avoid dependencies on Java 8's time library, for mobile as well as legacy applications.

import us.dustinj.timezonemap.TimeZoneMap;
// Initialize of a region that spans from Germany to Bulgaria.
// Takes some time (~1-5 seconds) to initialize, so try and initialize only once and keep it.
TimeZoneMap map = TimeZoneMap.forRegion(43.5, 8.0, 53.00, 26.0);
String berlin = map.getOverlappingTimeZone(52.518424, 13.404776).get().getZoneId(); // Returns "Europe/Berlin"
String prague = map.getOverlappingTimeZone(50.074154, 14.437403).get().getZoneId(); // Returns "Europe/Prague"
String budapest = map.getOverlappingTimeZone(47.49642, 19.04970).get().getZoneId(); // Returns "Europe/Budapest"
String milan = map.getOverlappingTimeZone(45.466677, 9.188258).get().getZoneId();   // Returns "Europe/Rome"
String adriaticSea = map.getOverlappingTimeZone(44.337, 13.8282).get().getZoneId(); // Returns "Etc/GMT-1"

If you're on Java 8 or above, you can convert the returned time zone into a proper java.util.TimeZone:

java.util.TimeZone timeZone = java.util.TimeZone.getTimeZone(berlin);
timeZone.observesDaylightTime(); // Returns true

<dependency>
    <groupId>us.dustinj.timezonemap</groupId>
    <artifactId>timezonemap</artifactId>
    <version>4.5</version>
</dependency>

This library has been tested down to Android SDK 19 (KitKat 4.4), which was released in 2013.

implementation('us.dustinj.timezonemap:timezonemap:4.5`) {
    // Exclude standard compression library
    exclude group: 'com.github.luben', module: 'zstd-jni'
}
// Import aar for native component compilation
implementation 'com.github.luben:zstd-jni:1.4.9-5@aar'

The code of the library is licensed under the MIT License.

The time zone data contained in library is licensed under the Open Data Commons Open Database License (ODbL).