Tag: java
All the articles with the tag "java".
MySQL Notes
MySQL study and development notes covering connection methods, data types, primary keys and indexes, storage engines, and transaction isolation levels. Through examples it discusses dirty reads, non-repeatable reads, phantom reads, and locks, and also records execution plan analysis, SQL optimization, and the roles of common logs.
Using the Elasticsearch Java API
Starting with the Search API request structure and Query DSL, this article explains how to organize Elasticsearch query conditions, sorting, returned fields, and pagination. Examples show how to convert DSL into Java API calls and enable request logging for debugging.
Using Log4j2 (Part 2): Changing Log Levels at Runtime
Two ways to adjust Log4j2 log levels without restarting an application: changing the configuration through JMX in JConsole, or calling the programmatic configuration API through an HTTP endpoint. A production troubleshooting scenario illustrates when each approach is useful.
Using Log4j2 (Part 1)
This post sorts out Log4j2's architecture and the responsibilities of each component, using UML class diagrams to explain how the configuration fits together. Through examples, it covers log output and rollover policies, uncaught exception handling, bridges from other logging frameworks, and how to enable and verify asynchronous logging.