Converting byte array to string without loosing data

Recently I had to deal with poor Redis interface, that didn't allowed to store bytes and it was not possible to update it or change. Redis handles bytes perfectly for keys and data, but there was no way to pass it. Standard solution for this task is to use Base64, but for my case overhead was too big as I had to store hundreds of millions of records. UTF is not good too, as it is ruining data. Finally, I found that right encoding for this task is to use ISO-8859-1 encoding and it works just fine.

new String([10,20,-30,126] as byte[], "ISO-8859-1").getBytes("ISO-8859-1");

Storing sessions in Redis with Spring Boot

Tomcat has nice support to use Redis for session replication with this awesome library. However Spring Boot launches embedded Tomcat, so there is no traditional XML configuration, it is still super easy to change default manager to use Redis for session replication, just define containerCustomizer bean, like:

@Configuration
@EnableAutoConfiguration
@ComponentScan
public class App {
  public App() {
  }

  @Bean
  public EmbeddedServletContainerCustomizer containerCustomizer(){
    return factory -> {
      TomcatEmbeddedServletContainerFactory containerFactory = (TomcatEmbeddedServletContainerFactory) factory;
      containerFactory.addContextValves(new RedisSessionHandlerValve());
      containerFactory.setTomcatContextCustomizers(Arrays.asList(context -> {
        context.setSessionTimeout(30);
        context.setManager(new RedisSessionManager(){{
          setHost("redis.server.com");
        }});
      }));
    };
  }

  public static void main(String[] args) throws Exception {
    SpringApplication.run(App.class, args);
  }
}

(this is syntax with new shiny Java 8 lambdas, but with few additional boring types it should compile in old Javas too).