Introducing full-stack Internet architecture technologies centered on Java
This article explains the most common MySQL table join types—including INNER, LEFT, RIGHT, FULL OUTER, and exclusive joins—by creating sample order and customer tables, inserting data, visualizing each join with diagrams, and providing the exact SQL statements and query results.
The article explains a junior developer's intermittent bug when adding a new order status with code 200, showing that Java's Integer cache and the use of == instead of equals cause the status check to fail, and provides the correct solution.
This article introduces binary trees, explains their Java representation, demonstrates pre-order, in-order, post-order, and level-order traversals, and provides implementations for creating full binary trees, counting nodes, computing height, and counting leaf nodes, complete with sample code and usage examples.
This article explains how to deploy and use Alibaba Canal to capture MySQL binlog changes, configure MySQL and Canal, and write Java code that listens to row‑level events for synchronizing data to other systems such as Redis or Elasticsearch.
This article explains why the synchronized keyword cannot lock local variables in Java, demonstrates the behavior with multithreaded code examples, and shows that only class member variables can be effectively synchronized to control concurrent access.
This article revisits a recent poll on MySQL field length, then presents a Java code example that uses the synchronized keyword on a locally created String variable, asking readers to determine whether this approach truly provides locking, and invites discussion on Java concurrency semantics.
This article explains MySQL's four transaction isolation levels—READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, and SERIALIZABLE—by creating a simple table, inserting test data, and running step‑by‑step SQL scripts that illustrate the behavior of each level, including phenomena such as dirty reads, non‑repeatable reads, phantom reads, and locking.
This article introduces Javaassist, a Java library for runtime bytecode manipulation, and demonstrates how to view compiled bytecode, add Maven dependencies, generate new classes, modify existing ones, insert fields and methods, and apply AOP‑style enhancements without changing source code.
This article explains the concept and inner workings of Spring Boot Starters, demonstrates how they simplify dependency management and auto‑configuration, and provides a step‑by‑step guide to creating and using a custom Starter with full code examples.
This article explains what a MySQL deadlock is, shows a concrete example using two conflicting transactions on a simple test table, demonstrates how to detect the deadlock with InnoDB status output, and provides practical tips for preventing deadlocks in production systems.
