Fix Spring Security integration docs sample

Resolves: #1306

docs/src/test/java/docs/security/SecurityConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2016 the original author or authors.
+ * Copyright 2014-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,7 +21,6 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.security.config.annotation.web.builders.HttpSecurity;
 import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;
-import org.springframework.session.ExpiringSession;
 import org.springframework.session.FindByIndexNameSessionRepository;
 import org.springframework.session.security.SpringSessionBackedSessionRegistry;
 
@@ -33,7 +32,7 @@ import org.springframework.session.security.SpringSessionBackedSessionRegistry;
 public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
 
 	@Autowired
-	FindByIndexNameSessionRepository<ExpiringSession> sessionRepository;
+	private FindByIndexNameSessionRepository sessionRepository;
 
 	@Override
 	protected void configure(HttpSecurity http) throws Exception {
@@ -45,7 +44,8 @@ public class SecurityConfiguration extends WebSecurityConfigurerAdapter {
 	}
 
 	@Bean
-	SpringSessionBackedSessionRegistry sessionRegistry() {
+	@SuppressWarnings("unchecked")
+	public SpringSessionBackedSessionRegistry sessionRegistry() {
 		return new SpringSessionBackedSessionRegistry(this.sessionRepository);
 	}
 }