Java Instant query() method

The query() method of Java Instant class is used to query the instant using the specified query. This method uses the specified query strategy object. The TemporalQuery object defines the logic to be used to obtain the result.

Syntax

Parameters

R - As we can see in the syntax, there is R which is denoted as a type parameter which specifies the type of the result.

query - It specifies the query to invoke. Parameters cannot be null.

Returns

It returns the query result. It may be returned Null value which is defined by the query.

Exception

DateTimeException - If unable to query (defined by the query)

ArithmeticException - If numeric overflow occurs (defined by the query)

Example 1

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.temporal.TemporalQueries;

public class InstantQueryExample1
{
	public static void main(String[] args) {
	ZoneId zone = ZoneId.of("America/Sao_Paulo");

LocalDateTime d = LocalDateTime.of(2016, 10, 16, 0, 0, 0, 0);
ZonedDateTime z = d.atZone(zone);
System.out.println(z.query(TemporalQueries.zone()));
	}
}

Output:

America/Sao_Paulo

Example 2

import java.time.Instant;
import java.time.temporal.TemporalQueries;
import java.time.temporal.TemporalUnit;

public class InstantQueryExample2 {

    public static void main(String... args) {
        Instant i = Instant.now();
        System.out.println(i);

        TemporalUnit q = i.query(TemporalQueries.precision());
        System.out.println(q);
    }
} 

Output:

2017-05-01T20:57:09.883Z
Nanos

Example 3

import java.time.LocalDate;
import java.time.temporal.TemporalQueries;

public class InstantQueryExample3 {
   public static void main(String[] args) {

      LocalDate d = LocalDate.parse("2018-03-03");
      System.out.printf("Local Date is %s%n",
         d.query(TemporalQueries.precision()));
   }
}

Output: