A simple UserDetailsAuthenticationProvider for SpringSecurity

app-context.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd"
		default-autowire="byName">

	<tx:annotation-driven />

	<!-- Scans within the base package of the application for @Components to configure as beans -->
	<context:component-scan base-package="your.package.here" />

</beans>

HardCodedUserDetailsAuthenticationProvider.java

package com.example;

import java.util.Collections;
import java.util.List;
import java.util.logging.Logger;

import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.authentication.dao.AbstractUserDetailsAuthenticationProvider;
import org.springframework.security.core.AuthenticationException;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;

public class HardCodedUserDetailsAuthenticationProvider extends AbstractUserDetailsAuthenticationProvider{

	private Logger logger = Logger.getLogger( getClass().getName() );
	private final String username, password;
	
	public HardCodedUserDetailsAuthenticationProvider(String username, String password) {
		super();
		this.username = username;
		this.password = password;
	}

	@Override
	protected void additionalAuthenticationChecks(UserDetails userDetails, UsernamePasswordAuthenticationToken authentication)
			throws AuthenticationException {
		logger.info( String.format("additionalAuthenticationChecks requested on %s details with %s authentication", userDetails, authentication) );
	}

	@Override
	protected UserDetails retrieveUser(String username,
			UsernamePasswordAuthenticationToken authentication)
			throws AuthenticationException {
		
		
		Object creds = authentication.getCredentials();
		if( creds != null && String.class.isAssignableFrom(creds.getClass()) ){
			String pw = (String) creds;
			if( this.username.equalsIgnoreCase(username) && this.password.equals(pw) ){
				boolean enabled = true, 
						accountNonExpired = true, 
						credentialsNonExpired = true, 
						accountNonLocked = true;
				List<GrantedAuthority> authorities = Collections.emptyList();
				User user = new User(username, pw, enabled, accountNonExpired, credentialsNonExpired, accountNonLocked, authorities );
				return user;
			}
			throw new BadCredentialsException("Invalid credentials!!");
		}
		
		// creds should never be null, so we shouldn't ever end up here
		throw new IllegalStateException("Unreachable code");
	}

	
	
}

security-config.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:security="http://www.springframework.org/schema/security"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:util="http://www.springframework.org/schema/util"
	xsi:schemaLocation="http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
		http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd 
        	">
    
    <bean id="org.springframework.security.authenticationManager" class="org.springframework.security.authentication.ProviderManager">
		<property name="providers">
			<util:list>
				<bean class="com.example.HardCodedUserDetailsAuthentcationProvider">
					<constructor-arg index="0" value="user"/>
					<constructor-arg index="1" value="password"/>
				</bean>
			</util:list>
		</property>
	</bean>
	
	<security:http entry-point-ref="authenticationProcessingFilterEntryPoint" use-expressions="true" >
		<security:form-login login-processing-url="/doLogin"/>
	    <security:anonymous />
	</security:http>
	
	<bean id="authenticationProcessingFilterEntryPoint" class="org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint">
		<property name="loginFormUrl" value="/login"/>
	</bean>

</beans>