Introducing full-stack Internet architecture technologies centered on Java
This article explains how to use MySQL's EXPLAIN statement to view execution plans, demonstrates creating sample order and customer tables, walks through each column of the EXPLAIN output, and shows how indexes affect query performance, providing a practical reference for database optimization.
This article explains how to set conditional breakpoints in IntelliJ IDEA to skip unnecessary iterations during debugging, illustrating the technique with a Java loop example and highlighting its usefulness for locating issues in complex code structures.
The article compares interview questions from ten years ago, which focused on basic Java concepts, with today's interviews that probe deep system design, distributed architecture, performance troubleshooting, and data consistency, highlighting the increasing difficulty and breadth of knowledge required for modern developers.
This article explains the nature of NULL in MySQL, demonstrates why comparisons with = or != fail, shows the correct IS NULL/IS NOT NULL syntax, and discusses how NULL behaves with DISTINCT, GROUP BY, ORDER BY, and aggregate functions.
This article explains a three‑step method—using top to locate the CPU‑hungry Java process, identifying the offending thread, and printing its stack with jstack—to pinpoint and resolve excessive CPU consumption in a Java application running on Linux.
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.
