Java 8 release represented a new stepping stone in the history of java. It marks the transition to functional style programming. Most of us are working with 8, but let's see what it was introduced in 9. It is a minor release, but we must understand where java is going because of the 6 month… Continue reading Java 9 features
B-Tree index structure
At some point we all worked with a relational database. We all had problems with query performance and we fixed them usually by first looking at indexes. We looked at the columns, at the foreign key for the presence of an index. We noticed there some kind of B-tree structure. Now I'm gonna explain how… Continue reading B-Tree index structure
Maven Archetypes
We found a structure that works for our service.(eg clean architecture). That means we have a domain layer, a data access and application layer and of course our presentation layer which can be a rest endpoints layer. Now we want all our services to respect this structure and also we don't want to manually copy… Continue reading Maven Archetypes
Maven BOM
BOM stands for Bill of Materials. Basically we can use it to store in one place all the dependencies with their versions. It's useful in the case microservices are used to make sure same versions are used everywhere. Of course this is not necessarily a requirement for microservices, as you have the choice to build… Continue reading Maven BOM
Profiling with Spring
Every application should have functional and non-functional tests. Non-functional include load and performance. So what happens when we do not meet the performance requirements? Obviously we try to figure out what is going on. This is called profiling. In this post I will write about how to profile an application with spring. Profiling an application… Continue reading Profiling with Spring
Domain driven design concepts
Lately I've been fascinated by the idea of domain driven design. Before diving more deeply into it we must understand the concepts that are being used. Entities Each object should be uniquely identified. The entity should contain those attributes that are required in order to uniquely identify the object. For example for a Car the… Continue reading Domain driven design concepts
How many exceptions?
We all know what exceptions are. We have checked and unchecked exceptions in java. Checked exceptions are for recovering. Like reading a file from disk. public class ReadFile { private AtomicInteger retryCount = new AtomicInteger(0); private static final int maxRetries = 3; private static Logger log = getLogger(ReadFile.class.getName()); private String readFromFile(String fileLocation) { StringBuilder resultStringBuilder… Continue reading How many exceptions?
(Bad) Business kills coding
We're all in this because we love to code. The code has no feelings, it is real and quantifiable. We want to write the best code possible, to be proud of it. We follow the principles and realize great things. We refactor it times after times. Then unit and integration tests come along. Static analysis… Continue reading (Bad) Business kills coding
Sagas in microservices
We all know that the shared data in microservices(if they are done right) is eventually consistent. This is due to the CAP theorem which states that availability is usually a better choice than consistency. In a previous post I wrote about having eventual consistency data using Eventuate. Since distributed transactions(2PC) are heavy with a bad… Continue reading Sagas in microservices
Code review flavors
I have seen lots of people who are doing code reviews and others who think it's just waste of time or they are not convinced about it. The latter are probably defensive and don't want for others to tell them how good or bad is their code. And most probably they don't write any kind… Continue reading Code review flavors
