import java.text.SimpleDateFormat;
import java.util.Date;
import java.time.Instant;
 
class Ideone {
	public static void main (String[] args) throws Exception {
		final SimpleDateFormat sdf = 
				new SimpleDateFormat("yyyy-MM-dd'T'hh:mm:ss.SSSXXX");
		final String timestamp = "2019-08-17T09:51:41.775+00:00";
		final long milli = sdf.parse(timestamp).toInstant().toEpochMilli();
		final String decoded = sdf.format(Date.from(Instant.ofEpochMilli(milli)));
		System.out.println(decoded);
	}
}

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