Q:

Error creating bean with name 'org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration':

I am developing Spring MVC+Security+MySQL example. I've taken a reference from http://www.mkyong.com/spring-security/spring-security-form-login-using-database/. In this project, I make some customization, in this I created "database.properties" file and trying to load it into the AppConfig.java. When I deployed this project I see below error coming. Please help!
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration.setFilterChainProxySecurityConfigurer(org.springframework.security.config.annotation.ObjectPostProcessor,java.util.List) throws java.lang.Exception; nested exception is org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.mkyong.config.SecurityConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: javax.sql.DataSource com.mkyong.config.SecurityConfig.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class com.mkyong.config.AppConfig: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.jdbc.datasource.DriverManagerDataSource com.mkyong.config.AppConfig.dataSource()] threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${mysql.jdbc.driver}]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1146)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:410)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4840)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5303)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1407)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1397)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void org.springframework.security.config.annotation.web.configuration.WebSecurityConfiguration.setFilterChainProxySecurityConfigurer(org.springframework.security.config.annotation.ObjectPostProcessor,java.util.List) throws java.lang.Exception; nested exception is org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.mkyong.config.SecurityConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: javax.sql.DataSource com.mkyong.config.SecurityConfig.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class com.mkyong.config.AppConfig: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.jdbc.datasource.DriverManagerDataSource com.mkyong.config.AppConfig.dataSource()] threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${mysql.jdbc.driver}]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:604)
    at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:87)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:286)
    ... 22 more
Caused by: org.springframework.beans.factory.BeanExpressionException: Expression parsing failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.mkyong.config.SecurityConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: javax.sql.DataSource com.mkyong.config.SecurityConfig.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class com.mkyong.config.AppConfig: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.jdbc.datasource.DriverManagerDataSource com.mkyong.config.AppConfig.dataSource()] threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${mysql.jdbc.driver}]
    at org.springframework.context.expression.StandardBeanExpressionResolver.evaluate(StandardBeanExpressionResolver.java:142)
    at org.springframework.beans.factory.support.AbstractBeanFactory.evaluateBeanDefinitionString(AbstractBeanFactory.java:1318)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:782)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:770)
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredMethodElement.inject(AutowiredAnnotationBeanPostProcessor.java:561)
    ... 24 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'com.mkyong.config.SecurityConfig': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: javax.sql.DataSource com.mkyong.config.SecurityConfig.dataSource; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class com.mkyong.config.AppConfig: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.jdbc.datasource.DriverManagerDataSource com.mkyong.config.AppConfig.dataSource()] threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${mysql.jdbc.driver}]
    at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:289)

My updated code, other files are unchanged.
database.properties
mysql.jdbc.driver=com.mysql.jdbc.Driver
mysql.url=jdbc:mysql://localhost:3306/test
mysql.username=root
mysql.password=root

AppConfig.java
@EnableWebMvc
@Configuration
@ComponentScan({ "com.mkyong.web.*" })
@Import({ SecurityConfig.class })
@PropertySource({"classpath:database.properties"})
public class AppConfig {

    @Value("${mysql.jdbc.driver}")
    private String driverClass;

    @Value("${mysql.url}")
    private String url;

    @Value("${mysql.username}")
    private String username;

    @Value("${mysql.password}")
    private String password;

    @Bean(name = "dataSource")
    public DriverManagerDataSource dataSource() {
        DriverManagerDataSource driverManagerDataSource = new DriverManagerDataSource();
        /*driverManagerDataSource.setDriverClassName("com.mysql.jdbc.Driver");
        driverManagerDataSource.setUrl("jdbc:mysql://localhost:3306/test");
        driverManagerDataSource.setUsername("root");
        driverManagerDataSource.setPassword("root");*/

        driverManagerDataSource.setDriverClassName(driverClass);
        driverManagerDataSource.setUrl(url);
        driverManagerDataSource.setUsername(username);
        driverManagerDataSource.setPassword(password);

        return driverManagerDataSource;
    }

    @Bean
    public InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setViewClass(JstlView.class);
        viewResolver.setPrefix("/WEB-INF/pages/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }
}

A:

java.lang.IllegalStateException: Could not load JDBC driver class
  [${mysql.jdbc.driver}]

Actually, the place holder ${mysql.jdbc.driver} is not resolved. 
You can have following placeholder configurer bean which will resolve this value placeholders.
@Bean
public static PropertySourcesPlaceholderConfigurer propertyPlaceholderConfigurer() {
    return new PropertySourcesPlaceholderConfigurer();
}

PropertySourcesPlaceholderConfigurer
Specialization of PlaceholderConfigurerSupport that resolves ${...}
  placeholders within bean definition property values and @Value
  annotations against the current Spring Environment and its set of
  PropertySources.

