@Target({ElementType.TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Constraint(validatedBy = { FieldValidator.class })
public @interface NotNullOn {

        String message() default "values Missing";

        Class<?>[] groups() default {};


        Class<? extends Payload>[] payload() default {};


}


public class FieldValidator implements ConstraintValidator<NotNullOn, Employee> {

    @Override
    public void initialize(NotNullOn constraintAnnotation) {
        //default method.
    }

    @Override
    public boolean isValid(Employee value, ConstraintValidatorContext context) {
        if (value == null){
            return false;
        }

        if (value.getLastName() == null) {
            context.disableDefaultConstraintViolation();
            context.buildConstraintViolationWithTemplate("lastName is required")
                    .addPropertyNode("lastName").addConstraintViolation();
            return false;
        }

        if (value.getLastName() != null){
                context.disableDefaultConstraintViolation();
                context.buildConstraintViolationWithTemplate("lastName is required for company address")
                    .addPropertyNode("lastName").addConstraintViolation();
                return false;
        }
        return true;

    }

}

public class Department {

    private Long deptId;

    private String deptName;

    private List<Employee> employees;


    public Long getDeptId() {
        return deptId;
    }


    public void setDeptId(Long deptId) {
        this.deptId = deptId;
    }


    public String getDeptName() {
        return deptName;
    }


    public void setDeptName(String deptName) {
        this.deptName = deptName;
    }


    public List<Employee> getEmployees() {
        return employees;
    }

    public void setEmployees(List<Employee> employees) {
        this.employees = employees;
    }


}

@NotNullOn
public class Employee {

    private String name;

    private String lastName;

    private Long phNum;

    private Long empId;


    public String getName() {
        return name;
    }


    public void setName(String name) {
        this.name = name;
    }


    public String getLastName() {
        return lastName;
    }


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


    public Long getPhNum() {
        return phNum;
    }


    public void setPhNum(Long phNum) {
        this.phNum = phNum;
    }


    public Long getEmpId() {
        return empId;
    }


    public void setEmpId(Long empId) {
        this.empId = empId;
    }

}