source: src/main/java/com/project/beautycenter/model/Termini.java

package com.project.beautycenter.model;

import javax.persistence.*;
import java.text.SimpleDateFormat;
import java.time.Instant;
import java.util.Date;
import java.util.LinkedHashSet;
import java.util.Set;

@Entity
@Table(name = "termini", schema = "project")
public class Termini {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "termin_id", nullable = false)
    private Integer id;

    @Column(name = "pocetok", nullable = false)

    private Instant pocetok;

    @Column(name = "vremetraenje")
    private Integer vremetraenje;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "user_id_vraboten", nullable = false)
    private Vraboteni vraboteni;

    @OneToMany(mappedBy = "termini")
    private Set<Rezervacija> rezervacijas = new LinkedHashSet<>();

    public Termini(Instant pocetok, Integer vremetraenje, Vraboteni vraboten) {
        this.pocetok = pocetok;
        this.vremetraenje = vremetraenje;
        this.vraboteni = vraboten;
    }

    public Termini() {
    }

    public Instant pocetokFormatted2() {
        String stringPocetok = this.pocetok.toString();

        String formatted = stringPocetok.substring(0, stringPocetok.length() - 1).concat("-02:00");
        return Instant.parse(formatted);

    }

    public Set<Rezervacija> getRezervacijas() {
        return rezervacijas;
    }

    public void setRezervacijas(Set<Rezervacija> rezervacijas) {
        this.rezervacijas = rezervacijas;
    }

    public Vraboteni getVraboteni() {
        return vraboteni;
    }

    public void setVraboteni(Vraboteni vraboteni) {
        this.vraboteni = vraboteni;
    }

    public Integer getVremetraenje() {
        return vremetraenje;
    }

    public void setVremetraenje(Integer vremetraenje) {
        this.vremetraenje = vremetraenje;
    }

    public Instant getPocetok() {
        return pocetok;
    }

    public void setPocetok(Instant pocetok) {
        this.pocetok = pocetok;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String format() {
        Date myDate = Date.from(pocetok);
        SimpleDateFormat formatter = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
        String formattedDate = formatter.format(myDate);
        return formattedDate;
    }

}