Of all the regular conference speakers on the Java circuit Venkat is my favorite. He has the ability to break down complex topics and make them very simple to understand. In addition to all of that he also shows you why you should care, and how whatever he is presenting can make your development life better. I always hope that when I am explaining something that I can do it 1/10th as good as he does as then it will probably come across pretty fairly understandable to the person that I am talking to.

It has been a crazy few months in startup land. The interesting thing for me about startups is no matter how crazy it is compared to corporate work, I find myself really content amidst the chaos. The big change here is we have decided to build our backend architecture in Go instead of Java. Having done Java for 19 years this is a big change, but for business decisions we decided that the trade offs with Go were better for our long term business needs than the trade offs with Java. Now that I have been using it for a few months I figured I would discuss some of the differences between the languages and what I like and dislike about each.

We have been discussing going to a more serverless architecture at work and so I decided that I should do some research to see where that stuff is now. When I was at Choose we used AWS Lambda to implement the backend of an abandoned shopping cart service. We would then use that data to drive an email campaign to encourage the users to come back and finish purchasing an energy plan. It had a huge effect in driving conversion rates and we were able to implement the service in about 25 lines of vanilla java code. I opted not to use Spring as I judged the startup times to be too slow for it to be worth it. To manage libraries we used the maven shade plugin in our build process to build a fat jar.

Java 9 we hardly knew ye, yet here we are and today was the GA release of Java 10. This is especially true for those of us using Spring boot as we just got official Java 9 support a couple of weeks ago and now 10 is out. From my standpoint the big features of the release are the Root Certificates. Java 9 shipped without root certificates if you used OpenJDK which in my mind makes it less useable as now you have to with that, you can’t just run it and go. That is what was keeping me on Oracle’s releases of Java. Now in Java 10 there is no difference with the oracle JDK and the OpenJDK so I will probably just deploy my apps on OpenJDK in the future. That simplifies Linux installation as now you can just run apt-get install and go. Before I used to have to add the ppa for Oracles and install it and then deal with the strong crypto policy files. All those old pain points are gone.

After upgrading my test app to Spring Boot 2.0 yesterday I decided to see how difficult the Java 9 upgrade was from there. I am happy to report that it was fairly trivial. I upgraded my maven pom to set the Java version to 9 and did a mvn clean install.

Immediately I see some no class def exceptions around javax.transaction.Transaction. I did some quick google searching and discovered the problem seems to be in the Maven Surefire plugin. I found a work around that said to set the version to 2.20.1 and added a command line flag of –add-modules javax.transaction. After doing that I was seeing errors around java.xml.bind. Doing some more searching I then added a second –add-modules java.xml.bind. This fixed the issue. In the course of doing so I found a link to the issue on apache’s website. Reading through the comments I ended up with a final configuration of 2.21.0 with the following options:

Upgrading to Java 9

Ever since Java 9 was released last fall, I have been wanting to upgrade our software at work to the new platform. I am not interested in the new module stuff, mostly I just want the convenience methods like List.of(), and the platform improvements. I think G1 by default looks good, the new representation for strings to save memory looks like a huge win, and all the performance numbers that I have seen show it to be a big win. Unfortunately this is not as straight forward as one should hope.

I came across this blog post today which I thought was really good. It is a deep dive into the default hashCode() implementation in java. To me the most amazing outcome of the piece is that if a given class is going to be accessed by multiple threads you really need to override hashCode otherwise biased locking is disabled. All in all it is an interesting look in the guts of the JVM and worth a read: default hashCode

Recently at work I worked on a project using Amazon AWS Lambda. This is a cool concept. Amazon calls it serverless computing, but really what it is, is abstracting the server so that you can just focus on a small task that needs to run.

In this case we had a rest endpoint that just stores some data in a database.  If we think about a traditional Spring Boot Microservice we would probably do Spring Data JPA, point it at a mysql DB, and then have some rest controllers that talk to a service tier which persists the data. With Spring Boot this isn’t much code, but you still have some embedded Tomcat Server and a fair amount of ceremony for doing something very simple. After building the app you will need to deploy it to Elastic Beanstalk instance or else an EC2 Nano Instance or something similar. That is a lot of DevOps overhead to do something very simple. With Lamdba we can create a simple class that takes a pojo java object (Jackson style). With Lambda you don’t have Hibernate, you are just dealing with raw JDBC but when you are just inserting 1 Row into a Database you don’t really need am object relational mapping. You then use Amazon’s API gateway to send any requests to an endpoint to the lambda function and you are all good to go.

I have an update on my slowdown issues on Sierra. It appears the real problem lies in the AWS Java SDK. After talking to the spring boot people via github they were able to narrow it down to an Amazon issue. I opened an issue on github with Amazon and they responded that the version of the SDK that ships in the current spring cloud has this issue in it, and it has been fixed in a newer version of the SDK. One of the big value propositions of Spring Boot to me and the release train concept of Spring Cloud or Spring Data is that it is a collection of dependencies that have all been tested together, which lowers my risk of using them together. So I opened a request with Spring Cloud AWS to upgrade their SDK. Unfortunately they don’t seem very timely in responding to issues as I notice it looks like there are no responses on any of the issues raised in the last 2 weeks.

Recently one of my friends was working on a Spring Boot project and he was having trouble finding an example of how to configure user login for his site with Spring Boot using JPA. I had mentioned that there is some mention of configuring security in Greg Turnquist’s book Learning Spring Boot. He had just purchased Spring Boot in Action and I don’t think he was rushing to grab another book, but he hadn’t been able to find a good online tutorial.