Clock displays server or client datetime live. AutoSync feature in server mode can sync the clock with server periodically.
<style>
    .ui-analog-clock {
        width: 200px;
    }
</style>
<div class="card">
    <h:form>
        <h5 class="mt-0">Client</h5>
        <p:clock />
        <h5>Server</h5>
        <p:clock pattern="HH:mm:ss dd.MM.yyyy" mode="server"/>
        <h5>Custom</h5>
        <p:clock mode="server" value="#{clockView.dateTime}"/>
        <h5>Analog</h5>
        <p:clock displayMode="analog"/>
    </h:form>
</div>
package org.primefaces.showcase.view.misc;
import java.io.Serializable;
import java.time.LocalDateTime;
import jakarta.annotation.PostConstruct;
import jakarta.faces.view.ViewScoped;
import jakarta.inject.Named;
@Named
@ViewScoped
public class ClockView implements Serializable {
    private LocalDateTime dateTime;
    @PostConstruct
    public void init() {
        dateTime = LocalDateTime.now().plusYears(37).plusMonths(3).plusHours(4);
    }
    public LocalDateTime getDateTime() {
        return dateTime;
    }
    public void setDateTime(LocalDateTime dateTime) {
        this.dateTime = dateTime;
    }
}