CREATE TABLE USERS (
    USERNAME NVARCHAR2(128) PRIMARY KEY,
    PASSWORD NVARCHAR2(128) NOT NULL,
    ENABLED CHAR(1) CHECK (ENABLED IN ('Y','N') ) NOT NULL
);


CREATE TABLE AUTHORITIES (
    USERNAME NVARCHAR2(128) NOT NULL,
    AUTHORITY NVARCHAR2(128) NOT NULL
);
ALTER TABLE AUTHORITIES ADD CONSTRAINT AUTHORITIES_UNIQUE UNIQUE (USERNAME, AUTHORITY);
ALTER TABLE AUTHORITIES ADD CONSTRAINT AUTHORITIES_FK1 FOREIGN KEY (USERNAME) REFERENCES USERS (USERNAME) ENABLE;

Spring Security 2.0 introduced support for group authorities in JdbcDaoImpl. The table structure if groups are enabled is as follows. You will need to adjust this schema to match the database dialect you are using.

create table groups (
    id bigint generated by default as identity(start with 0) primary key,
    group_name varchar_ignorecase(50) not null
);

create table group_authorities (
    group_id bigint not null,
    authority varchar(50) not null,
    constraint fk_group_authorities_group foreign key(group_id) references groups(id)
);

create table group_members (
    id bigint generated by default as identity(start with 0) primary key,
    username varchar(50) not null,
    group_id bigint not null,
    constraint fk_group_members_group foreign key(group_id) references groups(id)
);

Remember that these tables are only required if you are using the provided JDBC UserDetailsService implementation. If you write your own or choose to implement AuthenticationProvider without a UserDetailsService, then you have complete freedom over how you store the data, as long as the interface contract is satisfied.

The default schema works with the embedded HSQLDB database that is used in unit tests within the framework.

create table acl_sid(
    id bigint generated by default as identity(start with 100) not null primary key,
    principal boolean not null,
    sid varchar_ignorecase(100) not null,
    constraint unique_uk_1 unique(sid,principal)
);

create table acl_class(
    id bigint generated by default as identity(start with 100) not null primary key,
    class varchar_ignorecase(100) not null,
    constraint unique_uk_2 unique(class)
);

create table acl_object_identity(
    id bigint generated by default as identity(start with 100) not null primary key,
    object_id_class bigint not null,
    object_id_identity varchar_ignorecase(36) not null,
    parent_object bigint,
    owner_sid bigint,
    entries_inheriting boolean not null,
    constraint unique_uk_3 unique(object_id_class,object_id_identity),
    constraint foreign_fk_1 foreign key(parent_object)references acl_object_identity(id),
    constraint foreign_fk_2 foreign key(object_id_class)references acl_class(id),
    constraint foreign_fk_3 foreign key(owner_sid)references acl_sid(id)
);

create table acl_entry(
    id bigint generated by default as identity(start with 100) not null primary key,
    acl_object_identity bigint not null,
    ace_order int not null,
    sid bigint not null,
    mask integer not null,
    granting boolean not null,
    audit_success boolean not null,
    audit_failure boolean not null,
    constraint unique_uk_4 unique(acl_object_identity,ace_order),
    constraint foreign_fk_4 foreign key(acl_object_identity) references acl_object_identity(id),
    constraint foreign_fk_5 foreign key(sid) references acl_sid(id)
);

create table acl_sid(
    id bigserial not null primary key,
    principal boolean not null,
    sid varchar(100) not null,
    constraint unique_uk_1 unique(sid,principal)
);

create table acl_class(
    id bigserial not null primary key,
    class varchar(100) not null,
    constraint unique_uk_2 unique(class)
);

create table acl_object_identity(
    id bigserial primary key,
    object_id_class bigint not null,
    object_id_identity varchar(36) not null,
    parent_object bigint,
    owner_sid bigint,
    entries_inheriting boolean not null,
    constraint unique_uk_3 unique(object_id_class,object_id_identity),
    constraint foreign_fk_1 foreign key(parent_object)references acl_object_identity(id),
    constraint foreign_fk_2 foreign key(object_id_class)references acl_class(id),
    constraint foreign_fk_3 foreign key(owner_sid)references acl_sid(id)
);

create table acl_entry(
    id bigserial primary key,
    acl_object_identity bigint not null,
    ace_order int not null,
    sid bigint not null,
    mask integer not null,
    granting boolean not null,
    audit_success boolean not null,
    audit_failure boolean not null,
    constraint unique_uk_4 unique(acl_object_identity,ace_order),
    constraint foreign_fk_4 foreign key(acl_object_identity) references acl_object_identity(id),
    constraint foreign_fk_5 foreign key(sid) references acl_sid(id)
);

You will have to set the classIdentityQuery and sidIdentityQuery properties of JdbcMutableAclService to the following values, respectively:

CREATE TABLE acl_sid (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    principal BOOLEAN NOT NULL,
    sid VARCHAR(100) NOT NULL,
    UNIQUE KEY unique_acl_sid (sid, principal)
) ENGINE=InnoDB;

CREATE TABLE acl_class (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    class VARCHAR(100) NOT NULL,
    UNIQUE KEY uk_acl_class (class)
) ENGINE=InnoDB;

CREATE TABLE acl_object_identity (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    object_id_class BIGINT UNSIGNED NOT NULL,
    object_id_identity VARCHAR(36) NOT NULL,
    parent_object BIGINT UNSIGNED,
    owner_sid BIGINT UNSIGNED,
    entries_inheriting BOOLEAN NOT NULL,
    UNIQUE KEY uk_acl_object_identity (object_id_class, object_id_identity),
    CONSTRAINT fk_acl_object_identity_parent FOREIGN KEY (parent_object) REFERENCES acl_object_identity (id),
    CONSTRAINT fk_acl_object_identity_class FOREIGN KEY (object_id_class) REFERENCES acl_class (id),
    CONSTRAINT fk_acl_object_identity_owner FOREIGN KEY (owner_sid) REFERENCES acl_sid (id)
) ENGINE=InnoDB;

CREATE TABLE acl_entry (
    id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,
    acl_object_identity BIGINT UNSIGNED NOT NULL,
    ace_order INTEGER NOT NULL,
    sid BIGINT UNSIGNED NOT NULL,
    mask INTEGER UNSIGNED NOT NULL,
    granting BOOLEAN NOT NULL,
    audit_success BOOLEAN NOT NULL,
    audit_failure BOOLEAN NOT NULL,
    UNIQUE KEY unique_acl_entry (acl_object_identity, ace_order),
    CONSTRAINT fk_acl_entry_object FOREIGN KEY (acl_object_identity) REFERENCES acl_object_identity (id),
    CONSTRAINT fk_acl_entry_acl FOREIGN KEY (sid) REFERENCES acl_sid (id)
) ENGINE=InnoDB;

CREATE TABLE acl_sid (
    id BIGINT NOT NULL IDENTITY PRIMARY KEY,
    principal BIT NOT NULL,
    sid VARCHAR(100) NOT NULL,
    CONSTRAINT unique_acl_sid UNIQUE (sid, principal)
);

CREATE TABLE acl_class (
    id BIGINT NOT NULL IDENTITY PRIMARY KEY,
    class VARCHAR(100) NOT NULL,
    CONSTRAINT uk_acl_class UNIQUE (class)
);

CREATE TABLE acl_object_identity (
    id BIGINT NOT NULL IDENTITY PRIMARY KEY,
    object_id_class BIGINT NOT NULL,
    object_id_identity VARCHAR(36) NOT NULL,
    parent_object BIGINT,
    owner_sid BIGINT,
    entries_inheriting BIT NOT NULL,
    CONSTRAINT uk_acl_object_identity UNIQUE (object_id_class, object_id_identity),
    CONSTRAINT fk_acl_object_identity_parent FOREIGN KEY (parent_object) REFERENCES acl_object_identity (id),
    CONSTRAINT fk_acl_object_identity_class FOREIGN KEY (object_id_class) REFERENCES acl_class (id),
    CONSTRAINT fk_acl_object_identity_owner FOREIGN KEY (owner_sid) REFERENCES acl_sid (id)
);

CREATE TABLE acl_entry (
    id BIGINT NOT NULL IDENTITY PRIMARY KEY,
    acl_object_identity BIGINT NOT NULL,
    ace_order INTEGER NOT NULL,
    sid BIGINT NOT NULL,
    mask INTEGER NOT NULL,
    granting BIT NOT NULL,
    audit_success BIT NOT NULL,
    audit_failure BIT NOT NULL,
    CONSTRAINT unique_acl_entry UNIQUE (acl_object_identity, ace_order),
    CONSTRAINT fk_acl_entry_object FOREIGN KEY (acl_object_identity) REFERENCES acl_object_identity (id),
    CONSTRAINT fk_acl_entry_acl FOREIGN KEY (sid) REFERENCES acl_sid (id)
);

CREATE TABLE ACL_SID (
    ID NUMBER(18) PRIMARY KEY,
    PRINCIPAL NUMBER(1) NOT NULL CHECK (PRINCIPAL IN (0, 1 )),
    SID NVARCHAR2(128) NOT NULL,
    CONSTRAINT ACL_SID_UNIQUE UNIQUE (SID, PRINCIPAL)
);
CREATE SEQUENCE ACL_SID_SQ START WITH 1 INCREMENT BY 1 NOMAXVALUE;
CREATE OR REPLACE TRIGGER ACL_SID_SQ_TR BEFORE INSERT ON ACL_SID FOR EACH ROW
BEGIN
    SELECT ACL_SID_SQ.NEXTVAL INTO :NEW.ID FROM DUAL;
END;


CREATE TABLE ACL_CLASS (
    ID NUMBER(18) PRIMARY KEY,
    CLASS NVARCHAR2(128) NOT NULL,
    CONSTRAINT ACL_CLASS_UNIQUE UNIQUE (CLASS)
);
CREATE SEQUENCE ACL_CLASS_SQ START WITH 1 INCREMENT BY 1 NOMAXVALUE;
CREATE OR REPLACE TRIGGER ACL_CLASS_ID_TR BEFORE INSERT ON ACL_CLASS FOR EACH ROW
BEGIN
    SELECT ACL_CLASS_SQ.NEXTVAL INTO :NEW.ID FROM DUAL;
END;


CREATE TABLE ACL_OBJECT_IDENTITY(
    ID NUMBER(18) PRIMARY KEY,
    OBJECT_ID_CLASS NUMBER(18) NOT NULL,
    OBJECT_ID_IDENTITY NVARCHAR2(64) NOT NULL,
    PARENT_OBJECT NUMBER(18),
    OWNER_SID NUMBER(18),
    ENTRIES_INHERITING NUMBER(1) NOT NULL CHECK (ENTRIES_INHERITING IN (0, 1)),
    CONSTRAINT ACL_OBJECT_IDENTITY_UNIQUE UNIQUE (OBJECT_ID_CLASS, OBJECT_ID_IDENTITY),
    CONSTRAINT ACL_OBJECT_IDENTITY_PARENT_FK FOREIGN KEY (PARENT_OBJECT) REFERENCES ACL_OBJECT_IDENTITY(ID),
    CONSTRAINT ACL_OBJECT_IDENTITY_CLASS_FK FOREIGN KEY (OBJECT_ID_CLASS) REFERENCES ACL_CLASS(ID),
    CONSTRAINT ACL_OBJECT_IDENTITY_OWNER_FK FOREIGN KEY (OWNER_SID) REFERENCES ACL_SID(ID)
);
CREATE SEQUENCE ACL_OBJECT_IDENTITY_SQ START WITH 1 INCREMENT BY 1 NOMAXVALUE;
CREATE OR REPLACE TRIGGER ACL_OBJECT_IDENTITY_ID_TR BEFORE INSERT ON ACL_OBJECT_IDENTITY FOR EACH ROW
BEGIN
    SELECT ACL_OBJECT_IDENTITY_SQ.NEXTVAL INTO :NEW.ID FROM DUAL;
END;


CREATE TABLE ACL_ENTRY (
    ID NUMBER(18) NOT NULL PRIMARY KEY,
    ACL_OBJECT_IDENTITY NUMBER(18) NOT NULL,
    ACE_ORDER INTEGER NOT NULL,
    SID NUMBER(18) NOT NULL,
    MASK INTEGER NOT NULL,
    GRANTING NUMBER(1) NOT NULL CHECK (GRANTING IN (0, 1)),
    AUDIT_SUCCESS NUMBER(1) NOT NULL CHECK (AUDIT_SUCCESS IN (0, 1)),
    AUDIT_FAILURE NUMBER(1) NOT NULL CHECK (AUDIT_FAILURE IN (0, 1)),
    CONSTRAINT ACL_ENTRY_UNIQUE UNIQUE (ACL_OBJECT_IDENTITY, ACE_ORDER),
    CONSTRAINT ACL_ENTRY_OBJECT_FK FOREIGN KEY (ACL_OBJECT_IDENTITY) REFERENCES ACL_OBJECT_IDENTITY (ID),
    CONSTRAINT ACL_ENTRY_ACL_FK FOREIGN KEY (SID) REFERENCES ACL_SID(ID)
);
CREATE SEQUENCE ACL_ENTRY_SQ START WITH 1 INCREMENT BY 1 NOMAXVALUE;
CREATE OR REPLACE TRIGGER ACL_ENTRY_ID_TRIGGER BEFORE INSERT ON ACL_ENTRY FOR EACH ROW
BEGIN
    SELECT ACL_ENTRY_SQ.NEXTVAL INTO :NEW.ID FROM DUAL;
END;

Enables Spring Security debugging infrastructure. This will provide human-readable (multi-line) debugging information to monitor requests coming into the security filters. This may include sensitive information, such as request parameters or headers, and should only be used in a development environment.

If you use an <http> element within your application, a FilterChainProxy bean named "springSecurityFilterChain" is created and the configuration within the element is used to build a filter chain within FilterChainProxy. As of Spring Security 3.1, additional http elements can be used to add extra filter chains ^[10]. Some core filters are always created in a filter chain and others will be added to the stack depending on the attributes and child elements which are present. The positions of the standard filters are fixed (see the filter order table in the namespace introduction), removing a common source of errors with previous versions of the framework when users had to configure the filter chain explicitly in the FilterChainProxy bean. You can, of course, still do this if you need full control of the configuration.

All filters which require a reference to the AuthenticationManager will be automatically injected with the internal instance created by the namespace configuration (see the introductory chapter for more on the AuthenticationManager).

Each <http> namespace block always creates an SecurityContextPersistenceFilter, an ExceptionTranslationFilter and a FilterSecurityInterceptor. These are fixed and cannot be replaced with alternatives.

This element allows you to set the errorPage property for the default AccessDeniedHandler used by the ExceptionTranslationFilter, using the error-page attribute, or to supply your own implementation using theref attribute. This is discussed in more detail in the section on the ExceptionTranslationFilter.

This element allows for configuring a CorsFilter. If no CorsFilter or CorsConfigurationSource is specified and Spring MVC is on the classpath, a HandlerMappingIntrospector is used as the CorsConfigurationSource.

This element allows for configuring additional (security) headers to be send with the response. It enables easy configuration for several headers and also allows for setting custom headers through the header element. Additional information, can be found in the Security Headers section of the reference.

Adds Cache-Control, Pragma, and Expires headers to ensure that the browser does not cache your secured pages.

When enabled adds the Strict-Transport-Security header to the response for any secure request. This allows the server to instruct browsers to automatically use HTTPS for future requests.

When enabled adds the Public Key Pinning Extension for HTTP header to the response for any secure request. This allows HTTPS websites to resist impersonation by attackers using mis-issued or otherwise fraudulent certificates.

The list of pins

A pin is specified using the base64-encoded SPKI fingerprint as value and the cryptographic hash algorithm as attribute

When enabled adds the Content Security Policy (CSP) header to the response. CSP is a mechanism that web applications can leverage to mitigate content injection vulnerabilities, such as cross-site scripting (XSS).

When enabled adds the Referrer Policy header to the response.

When enabled adds the Feature Policy header to the response.

When enabled adds the X-Frame-Options header to the response, this allows newer browsers to do some security checks and prevent clickjacking attacks.

Adds the X-XSS-Protection header to the response to assist in protecting against reflected / Type-1 Cross-Site Scripting (XSS) attacks. This is in no-way a full protection to XSS attacks!

Add the X-Content-Type-Options header with the value of nosniff to the response. This disables MIME-sniffing for IE8+ and Chrome extensions.

Add additional headers to the response, both the name and value need to be specified.

Adds an AnonymousAuthenticationFilter to the stack and an AnonymousAuthenticationProvider. Required if you are using the IS_AUTHENTICATED_ANONYMOUSLY attribute.

This element will add Cross Site Request Forger (CSRF) protection to the application. It also updates the default RequestCache to only replay "GET" requests upon successful authentication. Additional information can be found in the Cross Site Request Forgery (CSRF) section of the reference.

This element is used to add a filter to the filter chain. It doesn’t create any additional beans but is used to select a bean of type javax.servlet.Filter which is already defined in the application context and add that at a particular position in the filter chain maintained by Spring Security. Full details can be found in the namespace chapter.

Defines the SecurityExpressionHandler instance which will be used if expression-based access-control is enabled. A default implementation (with no ACL support) will be used if not supplied.

Used to add an UsernamePasswordAuthenticationFilter to the filter stack and an LoginUrlAuthenticationEntryPoint to the application context to provide authentication on demand. This will always take precedence over other namespace-created entry points. If no attributes are supplied, a login page will be generated automatically at the URL "/login" ^[11] The behaviour can be customized using the <form-login> Attributes.

Adds a BasicAuthenticationFilter and BasicAuthenticationEntryPoint to the configuration. The latter will only be used as the configuration entry point if form-based login is not enabled.

This is a top-level element which can be used to inject a custom implementation of HttpFirewall into the FilterChainProxy created by the namespace. The default implementation should be suitable for most applications.

This element is used to define the set of URL patterns that the application is interested in and to configure how they should be handled. It is used to construct the FilterInvocationSecurityMetadataSource used by the FilterSecurityInterceptor. It is also responsible for configuring a ChannelProcessingFilter if particular URLs need to be accessed by HTTPS, for example. When matching the specified patterns against an incoming request, the matching is done in the order in which the elements are declared. So the most specific patterns should come first and the most general should come last.

<intercept-url> Attributes

• access Lists the access attributes which will be stored in the FilterInvocationSecurityMetadataSource for the defined URL pattern/method combination. This should be a comma-separated list of the security configuration attributes (such as role names).

• filters Can only take the value "none". This will cause any matching request to bypass the Spring Security filter chain entirely. None of the rest of the <http> configuration will have any effect on the request and there will be no security context available for its duration. Access to secured methods during the request will fail.

	Note
	This property is invalid for filter-security-metadata-source

• method The HTTP Method which will be used in combination with the pattern and servlet path (optional) to match an incoming request. If omitted, any method will match. If an identical pattern is specified with and without a method, the method-specific match will take precedence.

• pattern The pattern which defines the URL path. The content will depend on the request-matcher attribute from the containing http element, so will default to ant path syntax.

• request-matcher-ref A reference to a RequestMatcher that will be used to determine if this <intercept-url> is used.

• requires-channel Can be "http" or "https" depending on whether a particular URL pattern should be accessed over HTTP or HTTPS respectively. Alternatively the value "any" can be used when there is no preference. If this attribute is present on any <intercept-url> element, then a ChannelProcessingFilter will be added to the filter stack and its additional dependencies added to the application context.

If a <port-mappings> configuration is added, this will be used to by the SecureChannelProcessor and InsecureChannelProcessor beans to determine the ports used for redirecting to HTTP/HTTPS.

	Note
	This property is invalid for filter-security-metadata-source

• servlet-path The servlet path which will be used in combination with the pattern and HTTP method to match an incoming request. This attribute is only applicable when request-matcher is 'mvc'. In addition, the value is only required in the following 2 use cases: 1) There are 2 or more HttpServlet 's registered in the ServletContext that have mappings starting with '/' and are different; 2) The pattern starts with the same value of a registered HttpServlet path, excluding the default (root) HttpServlet '/'.

	Note
	This property is invalid for filter-security-metadata-source

Adds a J2eePreAuthenticatedProcessingFilter to the filter chain to provide integration with container authentication.

Adds a LogoutFilter to the filter stack. This is configured with a SecurityContextLogoutHandler.

Similar to <form-login> and has the same attributes. The default value for login-processing-url is "/login/openid". An OpenIDAuthenticationFilter and OpenIDAuthenticationProvider will be registered. The latter requires a reference to a UserDetailsService. Again, this can be specified by id, using the user-service-ref attribute, or will be located automatically in the application context.

The attribute-exchange element defines the list of attributes which should be requested from the identity provider. An example can be found in the OpenID Support section of the namespace configuration chapter. More than one can be used, in which case each must have an identifier-match attribute, containing a regular expression which is matched against the supplied OpenID identifier. This allows different attribute lists to be fetched from different providers (Google, Yahoo etc).

Attributes used when making an OpenID AX Fetch Request

By default, an instance of PortMapperImpl will be added to the configuration for use in redirecting to secure and insecure URLs. This element can optionally be used to override the default mappings which that class defines. Each child <port-mapping> element defines a pair of HTTP:HTTPS ports. The default mappings are 80:443 and 8080:8443. An example of overriding these can be found in the namespace introduction.

Provides a method to map http ports to https ports when forcing a redirect.

Adds the RememberMeAuthenticationFilter to the stack. This in turn will be configured with either a TokenBasedRememberMeServices, a PersistentTokenBasedRememberMeServices or a user-specified bean implementing RememberMeServices depending on the attribute settings.

Sets the RequestCache instance which will be used by the ExceptionTranslationFilter to store request information before invoking an AuthenticationEntryPoint.

Session-management related functionality is implemented by the addition of a SessionManagementFilter to the filter stack.

Adds support for concurrent session control, allowing limits to be placed on the number of active sessions a user can have. A ConcurrentSessionFilter will be created, and a ConcurrentSessionControlAuthenticationStrategy will be used with the SessionManagementFilter. If a form-login element has been declared, the strategy object will also be injected into the created authentication filter. An instance of SessionRegistry (a SessionRegistryImpl instance unless the user wishes to use a custom bean) will be created for use by the strategy.

Adds support for X.509 authentication. An X509AuthenticationFilter will be added to the stack and an Http403ForbiddenEntryPoint bean will be created. The latter will only be used if no other authentication mechanisms are in use (its only functionality is to return an HTTP 403 error code). A PreAuthenticatedAuthenticationProvider will also be created which delegates the loading of user authorities to a UserDetailsService.

Used to explicitly configure a FilterChainProxy instance with a FilterChainMap

Used within to define a specific URL pattern and the list of filters which apply to the URLs matching that pattern. When multiple filter-chain elements are assembled in a list in order to configure a FilterChainProxy, the most specific patterns must be placed at the top of the list, with most general ones at the bottom.

Used to explicitly configure a FilterSecurityMetadataSource bean for use with a FilterSecurityInterceptor. Usually only needed if you are configuring a FilterChainProxy explicitly, rather than using the<http> element. The intercept-url elements used should only contain pattern, method and access attributes. Any others will result in a configuration error.

The websocket-message-broker element has two different modes. If the websocket-message-broker@id is not specified, then it will do the following things:

If additional control is necessary, the id can be specified and a ChannelSecurityInterceptor will be assigned to the specified id. All the wiring with Spring’s messaging infrastructure can then be done manually. This is more cumbersome, but provides greater control over the configuration.

Defines an authorization rule for a message.

Every Spring Security application which uses the namespace must have include this element somewhere. It is responsible for registering the AuthenticationManager which provides authentication services to the application. All elements which create AuthenticationProvider instances should be children of this element.

Unless used with a ref attribute, this element is shorthand for configuring a DaoAuthenticationProvider. DaoAuthenticationProvider loads user information from a UserDetailsService and compares the username/password combination with the values supplied at login. The UserDetailsService instance can be defined either by using an available namespace element (jdbc-user-service or by using the user-service-ref attribute to point to a bean defined elsewhere in the application context). You can find examples of these variations in the namespace introduction.

<security:authentication-manager>
<security:authentication-provider ref="myAuthenticationProvider" />
</security:authentication-manager>
<bean id="myAuthenticationProvider" class="com.something.MyAuthenticationProvider"/>

Causes creation of a JDBC-based UserDetailsService.

select username, authority from authorities where username = ?

Authentication providers can optionally be configured to use a password encoder as described in the namespace introduction. This will result in the bean being injected with the appropriate PasswordEncoder instance.

Creates an in-memory UserDetailsService from a properties file or a list of "user" child elements. Usernames are converted to lower-case internally to allow for case-insensitive lookups, so this should not be used if case-sensitivity is required.

Represents a user in the application.

This element is the primary means of adding support for securing methods on Spring Security beans. Methods can be secured by the use of annotations (defined at the interface or class level) or by defining a set of pointcuts as child elements, using AspectJ syntax.

This element can be used to decorate an AfterInvocationProvider for use by the security interceptor maintained by the <global-method-security> namespace. You can define zero or more of these within the global-method-security element, each with a ref attribute pointing to an AfterInvocationProvider bean instance within your application context.

Allows the default expression-based mechanism for handling Spring Security’s pre and post invocation annotations (@PreFilter, @PreAuthorize, @PostFilter, @PostAuthorize) to be replaced entirely. Only applies if these annotations are enabled.

Defines the PrePostInvocationAttributeFactory instance which is used to generate pre and post invocation metadata from the annotated methods.

Customizes the PostInvocationAdviceProvider with the ref as the PostInvocationAuthorizationAdvice for the <pre-post-annotation-handling> element.

Customizes the PreInvocationAuthorizationAdviceVoter with the ref as the PreInvocationAuthorizationAdviceVoter for the <pre-post-annotation-handling> element.

<protect-pointcut> Rather than defining security attributes on an individual method or class basis using the @Secured annotation, you can define cross-cutting security constraints across whole sets of methods and interfaces in your service layer using the <protect-pointcut> element. You can find an example in the namespace introduction.

Can be used inside a bean definition to add a security interceptor to the bean and set up access configuration attributes for the bean’s methods

Creates a MethodSecurityMetadataSource instance

Defines a protected method and the access control configuration attributes that apply to it. We strongly advise you NOT to mix "protect" declarations with any services provided "global-method-security".

<ldap-server> Element This element sets up a Spring LDAP ContextSource for use by the other LDAP beans, defining the location of the LDAP server and other information (such as a username and password, if it doesn’t allow anonymous access) for connecting to it. It can also be used to create an embedded server for testing. Details of the syntax for both options are covered in the LDAP chapter. The actual ContextSource implementation is DefaultSpringSecurityContextSource which extends Spring LDAP’s LdapContextSource class. The manager-dn and manager-password attributes map to the latter’s userDn and password properties respectively.

If you only have one server defined in your application context, the other LDAP namespace-defined beans will use it automatically. Otherwise, you can give the element an "id" attribute and refer to it from other namespace beans using the server-ref attribute. This is actually the bean id of the ContextSource instance, if you want to use it in other traditional Spring beans.

This element is shorthand for the creation of an LdapAuthenticationProvider instance. By default this will be configured with a BindAuthenticator instance and a DefaultAuthoritiesPopulator. As with all namespace authentication providers, it must be included as a child of the authentication-provider element.

This is used as child element to <ldap-provider> and switches the authentication strategy from BindAuthenticator to PasswordComparisonAuthenticator.

This element configures an LDAP UserDetailsService. The class used is LdapUserDetailsService which is a combination of a FilterBasedLdapUserSearch and a DefaultLdapAuthoritiesPopulator. The attributes it supports have the same usage as in <ldap-provider>.

Spring Security provides you with a very flexible framework for your authentication and authorization requirements, but there are many other considerations for building a secure application that are outside its scope. Web applications are vulnerable to all kinds of attacks which you should be familiar with, preferably before you start development so you can design and code with them in mind from the beginning. Check out thehttp://www.owasp.org/[OWASP web site] for information on the major issues facing web application developers and the countermeasures you can use against them.

Let’s assume you’re developing an enterprise application based on Spring. There are four security concerns you typically need to address: authentication, web request security, service layer security (i.e. your methods that implement business logic), and domain object instance security (i.e. different domain objects have different permissions). With these typical requirements in mind:

For simple applications, servlet specification security may just be enough. Although when considered within the context of web container portability, configuration requirements, limited web request security flexibility, and non-existent services layer and domain object instance security, it becomes clear why developers often look to alternative solutions.

Spring Security 3.0 and 3.1 require at least JDK 1.5 and also require Spring 3.0.3 as a minimum. Ideally you should be using the latest release versions to avoid problems.

Spring Security 2.0.x requires a minimum JDK version of 1.4 and is built against Spring 2.0.x. It should also be compatible with applications using Spring 2.5.x.

What could be wrong?

Or subsititute an alternative complex scenario…​

Realistically, you need an understanding of the technolgies you are intending to use before you can successfully build applications with them. Security is complicated. Setting up a simple configuration using a login form and some hard-coded users using Spring Security’s namespace is reasonably straightforward. Moving to using a backed JDBC database is also easy enough. But if you try and jump straight to a complicated deployment scenario like this you will almost certainly be frustrated. There is a big jump in the learning curve required to set up systems like CAS, configure LDAP servers and install SSL certificates properly. So you need to take things one step at a time.

From a Spring Security perspective, the first thing you should do is follow the "Getting Started" guide on the web site. This will take you through a series of steps to get up and running and get some idea of how the framework operates. If you are using other technologies which you aren’t familiar with then you should do some research and try to make sure you can use them in isolation before combining them in a complex system.

This means that authentication has failed. It doesn’t say why, as it is good practice to avoid giving details which might help an attacker guess account names or passwords.

This also means that if you ask this question in the forum, you will not get an answer unless you provide additional information. As with any issue you should check the output from the debug log, note any exception stacktraces and related messages. Step through the code in a debugger to see where the authentication fails and why. Write a test case which exercises your authentication configuration outside of the application. More often than not, the failure is due to a difference in the password data stored in a database and that entered by the user. If you are using hashed passwords, make sure the value stored in your database is exactly the same as the value produced by the PasswordEncoder configured in your application.

A common user problem with infinite loop and redirecting to the login page is caused by accidently configuring the login page as a "secured" resource. Make sure your configuration allows anonymous access to the login page, either by excluding it from the security filter chain or marking it as requiring ROLE_ANONYMOUS.

If your AccessDecisionManager includes an AuthenticatedVoter, you can use the attribute "IS_AUTHENTICATED_ANONYMOUSLY". This is automatically available if you are using the standard namespace configuration setup.

From Spring Security 2.0.1 onwards, when you are using namespace-based configuration, a check will be made on loading the application context and a warning message logged if your login page appears to be protected.

This is a debug level message which occurs the first time an anonymous user attempts to access a protected resource.

DEBUG [ExceptionTranslationFilter] - Access is denied (user is anonymous); redirecting to authentication entry point
org.springframework.security.AccessDeniedException: Access is denied
at org.springframework.security.vote.AffirmativeBased.decide(AffirmativeBased.java:68)
at org.springframework.security.intercept.AbstractSecurityInterceptor.beforeInvocation(AbstractSecurityInterceptor.java:262)

It is normal and shouldn’t be anything to worry about.

The most common reason for this is that your browser has cached the page and you are seeing a copy which is being retrieved from the browsers cache. Verify this by checking whether the browser is actually sending the request (check your server access logs, the debug log or use a suitable browser debugging plugin such as "Tamper Data" for Firefox). This has nothing to do with Spring Security and you should configure your application or server to set the appropriate Cache-Control response headers. Note that SSL requests are never cached.

This is a another debug level message which occurs the first time an anonymous user attempts to access a protected resource, but when you do not have an AnonymousAuthenticationFilter in your filter chain configuration.

DEBUG [ExceptionTranslationFilter] - Authentication exception occurred; redirecting to authentication entry point
org.springframework.security.AuthenticationCredentialsNotFoundException:
                            An Authentication object was not found in the SecurityContext
at org.springframework.security.intercept.AbstractSecurityInterceptor.credentialsNotFound(AbstractSecurityInterceptor.java:342)
at org.springframework.security.intercept.AbstractSecurityInterceptor.beforeInvocation(AbstractSecurityInterceptor.java:254)

It is normal and shouldn’t be anything to worry about.

What’s wrong with my configuration?

Note that the permissions for an LDAP directory often do not allow you to read the password for a user. Hence it is often not possible to use the the section called “What is a UserDetailsService and do I need one?” where Spring Security compares the stored password with the one submitted by the user. The most common approach is to use LDAP "bind", which is one of the operations supported by the LDAP protocol. With this approach, Spring Security validates the password by attempting to authenticate to the directory as the user.

The most common problem with LDAP authentication is a lack of knowledge of the directory server tree structure and configuration. This will be different in different companies, so you have to find it out yourself. Before adding a Spring Security LDAP configuration to an application, it’s a good idea to write a simple test using standard Java LDAP code (without Spring Security involved), and make sure you can get that to work first. For example, to authenticate a user, you could use the following code:

@Test
public void ldapAuthenticationIsSuccessful() throws Exception {
        Hashtable<String,String> env = new Hashtable<String,String>();
        env.put(Context.SECURITY_AUTHENTICATION, "simple");
        env.put(Context.SECURITY_PRINCIPAL, "cn=joe,ou=users,dc=mycompany,dc=com");
        env.put(Context.PROVIDER_URL, "ldap://mycompany.com:389/dc=mycompany,dc=com");
        env.put(Context.SECURITY_CREDENTIALS, "joespassword");
        env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.ldap.LdapCtxFactory");

        InitialLdapContext ctx = new InitialLdapContext(env, null);

}

Session management issues are a common source of forum questions. If you are developing Java web applications, you should understand how the session is maintained between the servlet container and the user’s browser. You should also understand the difference between secure and non-secure cookies and the implications of using HTTP/HTTPS and switching between the two. Spring Security has nothing to do with maintaining the session or providing session identifiers. This is entirely handled by the servlet container.

When I open another browser window after logging in, it doesn’t stop me from logging in again. Why can I log in more than once?

Browsers generally maintain a single session per browser instance. You cannot have two separate sessions at once. So if you log in again in another window or tab you are just reauthenticating in the same session. The server doesn’t know anything about tabs, windows or browser instances. All it sees are HTTP requests and it ties those to a particular session according to the value of the JSESSIONID cookie that they contain. When a user authenticates during a session, Spring Security’s concurrent session control checks the number ofother authenticated sessions that they have. If they are already authenticated with the same session, then re-authenticating will have no effect.

With the default configuration, Spring Security changes the session ID when the user authenticates. If you’re using a Servlet 3.1 or newer container, the session ID is simply changed. If you’re using an older container, Spring Security invalidates the existing session, creates a new session, and transfers the session data to the new session. Changing the session identifier in this manner prevents"session-fixation" attacks. You can find more about this online and in the reference manual.

It doesn’t work - I just end up back at the login page after authenticating.

This happens because sessions created under HTTPS, for which the session cookie is marked as "secure", cannot subsequently be used under HTTP. The browser will not send the cookie back to the server and any session state will be lost (including the security context information). Starting a session in HTTP first should work as the session cookie won’t be marked as secure. However, Spring Security’s Session Fixation Protection can interfere with this because it results in a new session ID cookie being sent back to the user’s browser, usually with the secure flag. To get around this, you can disable session fixation protection, but in newer Servlet containers you can also configure session cookies to never use the secure flag. Note that switching between HTTP and HTTPS is not a good idea in general, as any application which uses HTTP at all is vulnerable to man-in-the-middle attacks. To be truly secure, the user should begin accessing your site in HTTPS and continue using it until they log out. Even clicking on an HTTPS link from a page accessed over HTTP is potentially risky. If you need more convincing, check out a tool like sslstrip.

Sessions are maintained either by exchanging a session cookie or by adding a jsessionid parameter to URLs (this happens automatically if you are using JSTL to output URLs, or if you call HttpServletResponse.encodeUrl on URLs (before a redirect, for example). If clients have cookies disabled, and you are not rewriting URLs to include the jsessionid, then the session will be lost. Note that the use of cookies is preferred for security reasons, as it does not expose the session information in the URL.

Make sure you have added the listener to your web.xml file. It is essential to make sure that the Spring Security session registry is notified when a session is destroyed. Without it, the session information will not be removed from the registry.

<listener>
        <listener-class>org.springframework.security.web.session.HttpSessionEventPublisher</listener-class>
</listener>

This usually means that the user’s application is creating a session somewhere, but that they aren’t aware of it. The most common culprit is a JSP. Many people aren’t aware that JSPs create sessions by default. To prevent a JSP from creating a session, add the directive <%@ page session="false" %> to the top of the page.

If you are having trouble working out where a session is being created, you can add some debugging code to track down the location(s). One way to do this would be to add a javax.servlet.http.HttpSessionListener to your application, which calls Thread.dumpStack() in the sessionCreated method.

If an HTTP 403 Forbidden is returned for HTTP POST, but works for HTTP GET then the issue is most likely related to CSRF. Either provide the CSRF Token or disable CSRF protection (not recommended).

Filters are not applied by default to forwards or includes. If you really want the security filters to be applied to forwards and/or includes, then you have to configure these explicitly in your web.xml using the <dispatcher> element, a child element of <filter-mapping>.

In a Spring web application, the application context which holds the Spring MVC beans for the dispatcher servlet is often separate from the main application context. It is often defined in a file called myapp-servlet.xml, where "myapp" is the name assigned to the Spring DispatcherServlet in web.xml. An application can have multiple DispatcherServlets, each with its own isolated application context. The beans in these "child" contexts are not visible to the rest of the application. The"parent" application context is loaded by the ContextLoaderListener you define in your web.xml and is visible to all the child contexts. This parent context is usually where you define your security configuration, including the <global-method-security> element). As a result any security constraints applied to methods in these web beans will not be enforced, since the beans cannot be seen from the DispatcherServlet context. You need to either move the <global-method-security> declaration to the web context or moved the beans you want secured into the main application context.

Generally we would recommend applying method security at the service layer rather than on individual web controllers.

Why can’t I see the user information?

If you have excluded the request from the security filter chain using the attribute filters='none' in the <intercept-url> element that matches the URL pattern, then the SecurityContextHolder will not be populated for that request. Check the debug log to see whether the request is passing through the filter chain. (You are reading the debug log, right?).

Method security will not hide links when using the url attribute in <sec:authorize> because we cannot readily reverse engineer what URL is mapped to what controller endpoint as controllers can rely on headers, current user, etc to determine what method to invoke.

The best way of locating classes is by installing the Spring Security source in your IDE. The distribution includes source jars for each of the modules the project is divided up into. Add these to your project source path and you can navigate directly to Spring Security classes (Ctrl-Shift-T in Eclipse). This also makes debugging easier and allows you to troubleshoot exceptions by looking directly at the code where they occur to see what’s going on there.

There is a general overview of what beans are created by the namespace in the namespace appendix of the reference guide. There is also a detailed blog article called "Behind the Spring Security Namespace" on blog.springsource.com. If want to know the full details then the code is in the spring-security-config module within the Spring Security 3.0 distribution. You should probably read the chapters on namespace parsing in the standard Spring Framework reference documentation first.

Spring Security has a voter-based architecture which means that an access decision is made by a series of AccessDecisionVoters. The voters act on the "configuration attributes" which are specified for a secured resource (such as a method invocation). With this approach, not all attributes may be relevant to all voters and a voter needs to know when it should ignore an attribute (abstain) and when it should vote to grant or deny access based on the attribute value. The most common voter is the RoleVoter which by default votes whenever it finds an attribute with the "ROLE_" prefix. It makes a simple comparison of the attribute (such as "ROLE_USER") with the names of the authorities which the current user has been assigned. If it finds a match (they have an authority called "ROLE_USER"), it votes to grant access, otherwise it votes to deny access.

The prefix can be changed by setting the rolePrefix property of RoleVoter. If you only need to use roles in your application and have no need for other custom voters, then you can set the prefix to a blank string, in which case the RoleVoter will treat all attributes as roles.

It will depend on what features you are using and what type of application you are developing. With Spring Security 3.0, the project jars are divided into clearly distinct areas of functionality, so it is straightforward to work out which Spring Security jars you need from your application requirements. All applications will need the spring-security-core jar. If you’re developing a web application, you need the spring-security-web jar. If you’re using security namespace configuration you need the spring-security-config jar, for LDAP support you need the spring-security-ldap jar and so on.

For third-party jars the situation isn’t always quite so obvious. A good starting point is to copy those from one of the pre-built sample applications WEB-INF/lib directories. For a basic application, you can start with the tutorial sample. If you want to use LDAP, with an embedded test server, then use the LDAP sample as a starting point. The reference manual also includeshttp://static.springsource.org/spring-security/site/docs/3.1.x/reference/springsecurity-single.html#appendix-dependencies[an appendix] listing the first-level dependencies for each Spring Security module with some information on whether they are optional and what they are required for.

If you are building your project with maven, then adding the appropriate Spring Security modules as dependencies to your pom.xml will automatically pull in the core jars that the framework requires. Any which are marked as "optional" in the Spring Security POM files will have to be added to your own pom.xml file if you need them.

If you are using Maven, you need to add the folowing to your pom dependencies:

<dependency>
        <groupId>org.apache.directory.server</groupId>
        <artifactId>apacheds-core</artifactId>
        <version>1.5.5</version>
        <scope>runtime</scope>
</dependency>
<dependency>
        <groupId>org.apache.directory.server</groupId>
        <artifactId>apacheds-server-jndi</artifactId>
        <version>1.5.5</version>
        <scope>runtime</scope>
</dependency>

The other required jars should be pulled in transitively.

UserDetailsService is a DAO interface for loading data that is specific to a user account. It has no other function other to load that data for use by other components within the framework. It is not responsible for authenticating the user. Authenticating a user with a username/password combination is most commonly performed by the DaoAuthenticationProvider, which is injected with a UserDetailsService to allow it to load the password (and other data) for a user in order to compare it with the submitted value. Note that if you are using LDAP, this approach may not work.

If you want to customize the authentication process then you should implement AuthenticationProvider yourself. See this blog article for an example integrating Spring Security authentication with Google App Engine.

How do I add support for extra login fields (e.g. a company name)?

This question comes up repeatedly in the Spring Security forum so you will find more information there by searching the archives (or through google).

The submitted login information is processed by an instance of UsernamePasswordAuthenticationFilter. You will need to customize this class to handle the extra data field(s). One option is to use your own customized authentication token class (rather than the standard UsernamePasswordAuthenticationToken), another is simply to concatenate the extra fields with the username (for example, using a ":" as the separator) and pass them in the username property of UsernamePasswordAuthenticationToken.

You will also need to customize the actual authentication process. If you are using a custom authentication token class, for example, you will have to write an AuthenticationProvider to handle it (or extend the standard DaoAuthenticationProvider). If you have concatenated the fields, you can implement your own UserDetailsService which splits them up and loads the appropriate user data for authentication.

You can’t do this, since the fragment is not transmitted from the browser to the server. The URLs above are identical from the server’s perspective. This is a common question from GWT users.

Obviously you can’t (without resorting to something like thread-local variables) since the only information supplied to the interface is the username. Instead of implementing UserDetailsService, you should implement AuthenticationProvider directly and extract the information from the supplied Authentication token.

In a standard web setup, the getDetails() method on the Authentication object will return an instance of WebAuthenticationDetails. If you need additional information, you can inject a custom AuthenticationDetailsSource into the authentication filter you are using. If you are using the namespace, for example with the <form-login> element, then you should remove this element and replace it with a <custom-filter> declaration pointing to an explicitly configured UsernamePasswordAuthenticationFilter.

You can’t, since the UserDetailsService has no awareness of the servlet API. If you want to store custom user data, then you should customize the UserDetails object which is returned. This can then be accessed at any point, via the thread-local SecurityContextHolder. A call to SecurityContextHolder.getContext().getAuthentication().getPrincipal() will return this custom object.

If you really need to access the session, then it must be done by customizing the web tier.

You can’t (and shouldn’t). You are probably misunderstanding its purpose. See "What is a UserDetailsService?" above.

People often ask about how to store the mapping between secured URLs and security metadata attributes in a database, rather than in the application context.

The first thing you should ask yourself is if you really need to do this. If an application requires securing, then it also requires that the security be tested thoroughly based on a defined policy. It may require auditing and acceptance testing before being rolled out into a production environment. A security-conscious organization should be aware that the benefits of their diligent testing process could be wiped out instantly by allowing the security settings to be modified at runtime by changing a row or two in a configuration database. If you have taken this into account (perhaps using multiple layers of security within your application) then Spring Security allows you to fully customize the source of security metadata. You can make it fully dynamic if you choose.

Both method and web security are protected by subclasses of AbstractSecurityInterceptor which is configured with a SecurityMetadataSource from which it obtains the metadata for a particular method or filter invocation. For web security, the interceptor class is FilterSecurityInterceptor and it uses the marker interface FilterInvocationSecurityMetadataSource. The "secured object" type it operates on is a FilterInvocation. The default implementation which is used (both in the namespace <http> and when configuring the interceptor explicitly, stores the list of URL patterns and their corresponding list of "configuration attributes" (instances of ConfigAttribute) in an in-memory map.

To load the data from an alternative source, you must be using an explicitly declared security filter chain (typically Spring Security’s FilterChainProxy) in order to customize the FilterSecurityInterceptor bean. You can’t use the namespace. You would then implement FilterInvocationSecurityMetadataSource to load the data as you please for a particular FilterInvocation ^[13]. A very basic outline would look something like this:

public class MyFilterSecurityMetadataSource implements FilterInvocationSecurityMetadataSource {

    public List<ConfigAttribute> getAttributes(Object object) {
        FilterInvocation fi = (FilterInvocation) object;
            String url = fi.getRequestUrl();
            String httpMethod = fi.getRequest().getMethod();
            List<ConfigAttribute> attributes = new ArrayList<ConfigAttribute>();

            // Lookup your database (or other source) using this information and populate the
            // list of attributes

            return attributes;
    }

    public Collection<ConfigAttribute> getAllConfigAttributes() {
        return null;
    }

    public boolean supports(Class<?> clazz) {
        return FilterInvocation.class.isAssignableFrom(clazz);
    }
}

For more information, look at the code for DefaultFilterInvocationSecurityMetadataSource.

The LdapAuthenticationProvider bean (which handles normal LDAP authentication in Spring Security) is configured with two separate strategy interfaces, one which performs the authentication and one which loads the user authorities, called LdapAuthenticator and LdapAuthoritiesPopulator respectively. The DefaultLdapAuthoritiesPopulator loads the user authorities from the LDAP directory and has various configuration parameters to allow you to specify how these should be retrieved.

To use JDBC instead, you can implement the interface yourself, using whatever SQL is appropriate for your schema:

public class MyAuthoritiesPopulator implements LdapAuthoritiesPopulator {
    @Autowired
    JdbcTemplate template;

    List<GrantedAuthority> getGrantedAuthorities(DirContextOperations userData, String username) {
        List<GrantedAuthority> = template.query("select role from roles where username = ?",
                                                                                                new String[] {username},
                                                                                                new RowMapper<GrantedAuthority>() {
            /**
             *  We're assuming here that you're using the standard convention of using the role
             *  prefix "ROLE_" to mark attributes which are supported by Spring Security's RoleVoter.
             */
            public GrantedAuthority mapRow(ResultSet rs, int rowNum) throws SQLException {
                return new SimpleGrantedAuthority("ROLE_" + rs.getString(1);
            }
        }
    }
}

You would then add a bean of this type to your application context and inject it into the LdapAuthenticationProvider. This is covered in the section on configuring LDAP using explicit Spring beans in the LDAP chapter of the reference manual. Note that you can’t use the namespace for configuration in this case. You should also consult the Javadoc for the relevant classes and interfaces.

What can I do short of abandoning namespace use?

The namespace functionality is intentionally limited, so it doesn’t cover everything that you can do with plain beans. If you want to do something simple, like modify a bean, or inject a different dependency, you can do this by adding a BeanPostProcessor to your configuration. More information can be found in the Spring Reference Manual. In order to do this, you need to know a bit about which beans are created, so you should also read the blog article in the above question on how the namespace maps to Spring beans.

Normally, you would add the functionality you require to the postProcessBeforeInitialization method of BeanPostProcessor. Let’s say that you want to customize the AuthenticationDetailsSource used by the UsernamePasswordAuthenticationFilter, (created by the form-login element). You want to extract a particular header called CUSTOM_HEADER from the request and make use of it while authenticating the user. The processor class would look like this:

public class BeanPostProcessor implements BeanPostProcessor {

        public Object postProcessAfterInitialization(Object bean, String name) {
                if (bean instanceof UsernamePasswordAuthenticationFilter) {
                        System.out.println("********* Post-processing " + name);
                        ((UsernamePasswordAuthenticationFilter)bean).setAuthenticationDetailsSource(
                                        new AuthenticationDetailsSource() {
                                                public Object buildDetails(Object context) {
                                                        return ((HttpServletRequest)context).getHeader("CUSTOM_HEADER");
                                                }
                                        });
                }
                return bean;
        }

        public Object postProcessBeforeInitialization(Object bean, String name) {
                return bean;
        }
}

You would then register this bean in your application context. Spring will automatically invoke it on the beans defined in the application context.