From Java 8 you can define static methods in interfaces in addition to default methods.
A static method is a method that is associated with the class in which it is defined rather than with any object. Every instance of the class shares its static methods.
This makes it easier for you to organize helper methods in your libraries; you can keep static methods specific to an interface in the same interface rather than in a separate class.
The following example defines a static method that retrieves a
ZoneId
object corresponding to a time zone identifier; it uses the system default time zone if there is noZoneId
object corresponding to the given identifier. (As a result, you can simplify the methodgetZonedDateTime
)
Here is code :
public interface TimeClient {
// ...
static public ZoneId getZoneId (String zoneString) {
try {
return ZoneId.of(zoneString);
} catch (DateTimeException e) {
System.err.println("Invalid time zone: " + zoneString +"; using default time zone instead.");
return ZoneId.systemDefault();
}
}
default public ZonedDateTime getZonedDateTime(String zoneString) {
return ZonedDateTime.of(getLocalDateTime(), getZoneId(zoneString));
}
}
See also
For all interesting things in Java 8 read Everything about Java 8