How to open new tab from the java code?

Need to open a new tab in the browser from the java code, this is my view the code should be opened in a new tab.

public String update() {
    this.conversation.end();

    try {
        if (this.id == null) {
            this.entityManager.persist(this.voucher); 
            //open in new tab
            return "view?faces-redirect=true&id=" + this.voucher.getId();               
        } else {             
            this.entityManager.merge(this.voucher);
            //open in new tab   
            return "view?faces-redirect=true&id=" + this.voucher.getId();
        }
    } catch (Exception e) {
        FacesContext.getCurrentInstance().addMessage(null,
                new FacesMessage(e.getMessage()));
        return null;
    }
}