In this article, we will explain how to use and debug HikariCP Pool for JDBC SQL with Logback. The goal is to be able to monitor how many connections are opened / closed by the connection pool. We will do a multi-thread load test of SQL requests on the pool, and see how it reacts. […]
Category: Java
In this tutorial, we will see how JDBC Java transactions rollbacks are useful, with a real world example and a full Java demo. We will look at the particular case of batch inserts. 1) Batch inserts without rollback Let’s use the following SQL table: Starting from a JDBC connection object called conn: , the batch […]
In this tutorial, we will see how to batch SQL insert queries, using Java JDBC. Then, we will do a performance test to compare batched inserts VS non-batched inserts. 1) The SQL table We will use the following table: 2) Batch inserts Starting from a JDBC connection object called conn: simply do: We use the […]
In this quick tutorial, we will explain how to download an image directly with Selenium in Java. The advantage of this method, instead of using a classic HTTP client like CURL, is that the website will behave exactly the same way as if you were browsing it with a classic browser like Chrome. 1) Setup […]
In this quick tutorial, we will see how to scroll slowly to the bottom of a web page, using Puppeteer Java and Playwright. Playwright is a new browser automation framework developed by Microsoft. It is based on JavaScript Puppeteer. Look here for a quick tutorial on how to use Playwright in Java. 1) Compute the […]
In this short tutorial, we will see how to do browser automation with a Java equivalent of JavaScript Puppeteer: a new framework developed by Microsoft called Playwright. 1) Import the dependency in your pom.xml In your pom.xml file, add: <dependency> <groupId>com.microsoft.playwright</groupId> <artifactId>playwright</artifactId> <version>1.15.2</version> </dependency> 2) Open Firefox and navigate to Wikipedia.com To open a Firefox […]
In this short tutorial, we will see how to easily run a private docker image using Java TestContainers. We will use a private AWS ECR registry, but the code will work the same with any other private registry. 1) Needed parameters First, you need to gather the following parameters: String registry = “601730646169.dkr.ecr.us-west-2.amazonaws.com”; String image […]
How to pretty print a database SQL schema (table names, columns names and types), in Java using JDBC. Starting from a JDBC connection object to your database called conn: java.sql.Connection conn; simply do: The console output is the following: client ——————————————————————– id : uuid name : varchar product ——————————————————————– id : uuid name : varchar […]
In this short tutorial, we will see how to map and filter a list with Java lambdas. 1) Map a list Let’s start from a list of integers: List<Integer> list = List.of(1, 3, 6, 2, 4, 5); To map the list, we need to convert it into a stream, then map it and finally collect […]
In this tutorial we will see how to create an index on a SQL table column with JDBC, then we will fill a table with 10⁷ rows (using PostgreSQL fast COPY function), and finally we will compare the select performance with vs without the index. 1) The SQL tables and the index We will create […]