/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
import java.math.BigDecimal;
 
import java.time.* ;
import java.time.temporal.* ;
import java.time.format.* ;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
 
        String input = "1493694000000";
        BigDecimal bd = new BigDecimal( input );
        BigDecimal microsDivisor = new BigDecimal( 1_000_000_000L );
        long seconds = bd.longValue( );
        BigDecimal bdMicros = bd.subtract( new BigDecimal( seconds ) ).multiply( microsDivisor );
        long nanos = bdMicros.longValue( );
 
        Instant instant = Instant.ofEpochSecond( seconds , nanos );
 
        System.out.println( "input: " + input + " = bd: " + bd + " = seconds: " + seconds + " & nanos: " + nanos );
        System.out.println( "instant.toString(): " + instant );
 
 
	}
}

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