public class TestJava {

    public static void main(String args[]) {
        List<PhoneModel> listReturn=new ArrayList<>();

        for (int i = 0; i < 10; i++) {
            PhoneModel model=new PhoneModel();
            model.setFirstName(".");
            model.setMiddleName("Петрович"+i);
            model.setLastName("Family1");
            model.setCheckNumber(141111414);
            if (i==1) {
                model.setFirstName(" 1");
                model.setLastName("Family100");
            }
            if (i==2) {
                model.setFirstName(" 2");
                model.setLastName("Family2");
            }
            if (i==3) {
                model.setFirstName("");
                model.setLastName("Family10000");
            }
            if (i==4) {
                model.setFirstName(" 4");
                model.setLastName("Family4");
            }
            if (i==5) {
                model.setFirstName(" 5");
                model.setLastName("Family5");
            }
            listReturn.add(model);
        }

        Collections.sort(listReturn, new ComparatorSort(true));
    }
}









public class ComparatorSort implements Comparator<PhoneModel> {
    private boolean byFirstName;
    private String strA,strB;
    private Collator collator;

    public ComparatorSort(boolean byFirstName) {
        this.byFirstName=byFirstName;
        collator=Collator.getInstance(Locale.getDefault());
    }

    @Override
    public int compare(PhoneModel o1, PhoneModel o2) {
        if (byFirstName) {
            strA = o1.getFirstName().toLowerCase();
            strB = o2.getFirstName().toLowerCase();
        } else {
            strA = o1.getLastName().toLowerCase();
            strB = o2.getLastName().toLowerCase();
        }

        if (strA.isEmpty()) {
            System.out.println(o1.getMiddleName());
            return 100;
        } else {
            System.out.println(o1.getMiddleName());
            return collator.compare(strA, strB);
        }
        //return collator.compare(strA,strB);
    }
}













public class PhoneModel implements Cloneable, Serializable {
    private String id;
    private String firstName="";
    private String lastName="";
    private String middleName="";
    private List<String> listNumber;
    private int checkNumber=0;

    public String getMiddleName() {
        return middleName;
    }

    public void setMiddleName(String middleName) {
        this.middleName = middleName;
    }

    @Override
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }

    public PhoneModel() {
        this.listNumber = new ArrayList<>();
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getId() {
        return id;
    }

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

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public List<String> getListNumber() {
        return listNumber;
    }

    public int getCheckNumber() {
        return checkNumber;
    }

    public void setCheckNumber(int checkNumber) {
        this.checkNumber = checkNumber;
    }
}