Freaks City

In enterprise Java development, the @Transactional annotation is widely used to manage database transactions. However, developers often encounter situations where the transaction does not roll back as expected. This article explores the fundamental concepts of transactions and lists the most common scenarios that cause Spring-managed transactio ...

Bean Scopes in Spring When the Spring IoC container starts, it reads bean definitions from configuration files (e.g., XML) and converts each <bean> element into a BeanDefinition object. The scope attribute within BeanDefinition determines the bean's scope. Spring provides five built-in scopes, three of which are only available in a web-aw ...

Java Primitive Types Java supports eight primitive data types: 8-bit: byte 16-bit: short, char 32-bit: int, float 64-bit: long, double boolean Java Data Structures Arrays Arrays offer O(1) access time via index, making them excellent for random access operations and sequential iteration. However, their size is fixed at creation time, preventi ...

Transaction management belongs logically in the service layer. Spring supports two primary approaches: Programmatic transaction management (for advanced use cases) Declarative transaction management (recommended for most applications) Declarative transactions can be implemented either via XML configuration or annotations — the latter being th ...

1. Example: One Person and Two Pets 1.1 Cat class public class Cat { public void Cry() { System.out.println("Hiss"); } } 1.2 Dog class public class Dog { public void Cry() { System.out.println("Bark"); } } 1.3 People class public class People { private String name; private Cat cat ...

Problem Statement In a flash sale system, I encountered a scenario where one aspect handles Redis-based distributed locking and rate limiting, while another aspect is responsible for publishing order messages to a message queue. The core challenge: how to transmit data computed in the first aspect to the second aspect for further processing. So ...

Core Concepts of Interceptors In Spring applications, interceptors serve as middleware components designed to execute custom logic before or after HTTP requests are processed. Unlike Aspect-Oriented Programming (AOP), which targets method-level cross-cutting concerns, interceptors specifically focus on the request processing pipeline. Intercept ...

AOP enables method enhancement without modifying the original source code (enhancement = proxy). AOP Pointcut Expression Syntax: execution([access modifier] [return type] [full class path] [method name] ([parameter list])) Example: @Before(value = "execution(* com.example.service.AccountService.deposit(..))") Join Point Any method w ...

Prior to the introduction of Spring 3.x, configuration in Spring primarily relied on XML files. With the release of Spring 3.x, JavaConfig was introduced as a method of configuration based on Java code. This approach allows developers to define Spring container configurations and manage Spring beans through Java code, eliminating the need for e ...

Defining the Custom Constraint Annotation import javax.validation.Constraint; import javax.validation.Payload; import java.lang.annotation.*; @Constraint(validatedBy = RecordIdValidator.class) @Target({ElementType.FIELD}) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface RecordExists { String message() default "The pr ...