Wednesday, July 19, 2017

Hibernate MappedBy Example (like @OneToOne, @OneToMany, @ManyToMany)

Using "mappedBy" attribute of mapping annotations(like @OneToOne, @OneToMany, @ManyToMany) for bi-directional relationship. This attribute allows you to refer the associated entities from both sides. If "X" has association with "Y" then you can get X from Y and Y from X.

You can download source code from Github MappedByExample

1) OneToOne

    Book and Author
        id, email, name, phone
        1,, name, 543653465

        id, content, title, author_id
        1, re  td e sdf asdfasdfasd f, java, 1

2) OneToMany

    Person and Phone
        id, firstName, lastName
        1, Saurabh, Chaudhari

        id, network, number, person_id
        1, BSNL, 0987654321, 1
        2, Vodafone, 1234567890, 1

3) ManyToMany

    Employee and Department
        id, firstName, lastName
        1, Saurabh, Chaudhari

        id, name
        1, QA
        2, Software Engineer
        employees_id, departments_id
        1, 1
        1, 2

Spring JSP Enum in Select/Combo box

This post demonstrate that how to use Enum values in JSP page with Spring Framework

Java Class:

public class User{
    private String name;
    private UserType userType;

    setter and getter

Enum Class:

public enum UserType {
    ADMIN("Admin"), USER("User"), TEACHER("Teacher"), STUDENT("Student");

    private String code;

    UserType(String code) {
        this.code = code;

    public String getCode() {
        return code;

    public static UserType fromCode(String userType) {
        for (UserType uType : UserType.values()) {
        if (uType.getCode().equals(userType)) {
            return uType;
        throw new UnsupportedOperationException("The code " + userType + " is not supported!");

How to copy properties from one Java bean to another?

We can copy properties from one Java bean to another using Java Reflection API.

public static <T> void copy(T target, T source) throws Exception {
    Class<?> clazz = source.getClass();

    for (Field field : clazz.getDeclaredFields()) {
        if (Modifier.isPrivate(field.getModifiers()))
        Object value = field.get(source);
        field.set(target, value);

Spring Security Java Configuration Annotation Example

This application demonstrate how to use spring security in spring mvc application. This is java config annotation based configuration. I tried to implement following customization on spring security framework.

  1. Custom Authentication Provider.
  2. Custom UserDetailsService.
  3. Custom LoginSuccessHandler
  4. Custom AuthenticationFailureHandler
  5. Custom AccessDecisionVoter
  6. Update Current LoggedIn UserDetails
  7. Display All LoggedIn User In Application.
  8. Custom taglib to show/hide action based on user's role and permission.
  9. Prevent multiple login for same user (spring security concurrent user login prevention).
  10. Override spring security message as custom message.
  11. Expiring all Sessions of a LoggedIn Users.
  12. How to implement apache tiles template engine for multiple layout on JSP page.
 You can download source code from SpringSecurityMVC

public class SecurityConfig extends WebSecurityConfigurerAdapter {

    CustomAuthenticationProvider customAuthenticationProvider;

    UserDetailsService userDetailsService;

    LoginSuccessHandler loginSuccessHandler;

    LoginFailHandler loginFailHandler;

    public SecurityConfig() {

    public void configureGlobalSecurity(AuthenticationManagerBuilder auth) throws Exception {

    protected void configure(HttpSecurity http) throws Exception {
                .antMatchers(UrlMapping.getLoginUrl(), UrlMapping.getSignInUrl())
                        .deleteCookies("JSESSIONID", "SESSION")

    public void configure(WebSecurity web) throws Exception {
//        super.configure(web);

    PasswordEncoder encoder() {
        return new BCryptPasswordEncoder(15);

    public AccessDecisionManager accessDecisionManager() {
        List<AccessDecisionVoter<? extends Object>> decisionVoters = Arrays.asList(new WebExpressionVoter(),
                new RoleVoter(), new AuthenticatedVoter(), new MinuteBasedVoter());
        return new UnanimousBased(decisionVoters);

    public SessionRegistry sessionRegistry() {
        return new SessionRegistryImpl();

    public HttpSessionEventPublisher httpSessionEventPublisher() {
        return new HttpSessionEventPublisher();

    ConcurrentSessionControlAuthenticationStrategy concurrentSessionControlAuthenticationStrategy() {
        ConcurrentSessionControlAuthenticationStrategy csca = new ConcurrentSessionControlAuthenticationStrategy(
        return csca;

Spring 4 Jdbc Template CRUD

How to use Jdbc Template in Spring MVC application using Java Config

You can download source code from Spring4JdbcTemplate

public JdbcTemplate jdbcTemplate(DataSource dataSource) {
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);
return jdbcTemplate;

public PlatformTransactionManager txManager() {
return new DataSourceTransactionManager(dataSource());

public interface EmployeeDao {
public void save(Employee employee);
public void update(Employee employee, Integer id);
public void delete(Integer id);
public Employee get(Integer id);
public List<Employee> list();