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A Guide to Java Garbage Collection Tuning and Analysis

Selecting the right garbage collector is the first step in JavaGC tuning. Serial, Parallel, G1, ZGC or Shenandoah according to application needs; 2. Enable GC logs (Java8 uses -XX: PrintGCDetails, Java9 uses -Xlog) to collect GC behavior data; 3. Monitor key indicators such as pause time, GC frequency, heap usage trend, throughput and object promotion rate, and use tools such as gceasy.io to analyze logs; 4. For frequent young generation GCs, it can be solved by increasing the size of young generations or enabling adaptive strategies; 5. Long-term FullGC should be switched to G1, ZGC or Shenandoah to avoid display

Jul 31, 2025 am 03:35 AM

Full-Stack Web Development with Java, Spring Boot, and React

Selecting the Java SpringBoot React technology stack can build stable and efficient full-stack web applications, suitable for small and medium-sized to large enterprise-level systems. 2. The backend uses SpringBoot to quickly build RESTfulAPI. The core components include SpringWeb, SpringDataJPA, SpringSecurity, Lombok and Swagger. The front-end separation is achieved through @RestController returning JSON data. 3. The front-end uses React (in conjunction with Vite or CreateReactApp) to develop a responsive interface, uses Axios to call the back-end API, and ReactRouter

Jul 31, 2025 am 03:33 AM

java

The Role of the `volatile` Keyword in Java Concurrency

The volatile keyword ensures the visibility of variables and prohibits instruction reordering in a multi-threaded environment. 1. Using volatile can ensure that one thread’s modification of variables is immediately visible to other threads, avoiding inconsistent values caused by CPU cache; 2. volatile prevents instruction reordering through happens-before rules, ensuring that modifications before write operations are visible to subsequent read operations; 3. It is suitable for simple scenarios such as status flags, such as shutdown flags; 4. However, it does not guarantee the atomicity of composite operations, such as count, still requires AtomicInteger or lock mechanism; 5. volatile cannot replace the synchronization mechanism to achieve complete thread safety. Therefore, volatile

Jul 31, 2025 am 03:32 AM

java concurrent

Benchmarking Java Code Performance with JMH

JMH is a framework for writing precise Java microbenchmarks that can avoid measurement deviations caused by JVM optimization. 1. Use Maven or Gradle to add jmh-core and jmh-generator-annprocess dependencies and enable annotation processing. 2. Write benchmark test methods and annotate configuration parameters with @Benchmark, @BenchmarkMode, @Warmup, @Measurement, @Fork, etc. 3. The return value of the time-consuming operation is prevented from being eliminated by JIT optimization through return or Blackhole.consume(). 4. Use @State(Scope.Thread) to define the status class

Jul 31, 2025 am 03:32 AM

Java Concurrency in Practice: The Executor Framework

ExecutorFramework is a concurrency tool in Java for simplifying thread management and task scheduling. Its core is to decouple task submission from execution. 1. The reasons for using Executor instead of newThread() include avoiding resource out of control, improving performance, realizing thread reuse and unified management; 2. The main interfaces are Executor and the extension interface ExecutorService, which supports task submission, life cycle management and return of Future results; 3. Common thread pool types include newFixedThreadPool, newCachedThreadPool, newSingleThreadExecutor and newSc

Jul 31, 2025 am 01:52 AM

java concurrent

GraphQL APIs with Java and Spring for GraphQL

First, choose SpringforGraphQL for its official support, annotation driver, zero configuration startup, compatibility and ease of testing; 1. Add spring-boot-starter-graphql dependency and optionally add Web and GraphiQL support; 2. Define Query and Book types in schema.graphqls; 3. Create Book classes and use Lombok to simplify the code; 4. Use @Controller and @QueryMapping to implement bookById and allBooks queries; 5. After starting the application, use http://localhost:8080/graphi

Jul 31, 2025 am 01:46 AM

Java Memory Management and Avoiding Memory Leaks

Java memory leaks mainly occur in the heap area. Common scenarios include static collection classes holding object references, not closing resources, not logged out of the listener, implicitly holding external class references, and improper use of ThreadLocal; 2. The solutions are: using weak references or limiting cache size, using try-with-resources to automatically close resources, manually logging out listeners or using weak references, declaring the internal class as static, and using remove() to clean ThreadLocal; 3. Detection methods include using jstat/jmap/jvisualvm and other JVM tools, EclipseMAT to analyze heap dump files, and enabling GC logs to observe memory changes; 4. The best

Jul 31, 2025 am 01:22 AM

memory leak java memory management

Java Message Service (JMS) with ActiveMQ for Asynchronous Communication

JMS is the message communication API standard of the Java platform, supporting point-to-point and publish/subscribe models, and ActiveMQ is the message middleware it implements; 1. Start ActiveMQ service and listen to the default port; 2. Add activemq-client dependency in the Maven project; 3. Create producers to send messages to queues through ConnectionFactory; 4. Create consumers to receive messages asynchronously through MessageListener; this combination realizes system decoupling, traffic peak cutting, reliable delivery and asynchronous processing, and is suitable for traditional Java enterprise applications. Although there are more modern alternatives, they still have learning and use value.

Jul 31, 2025 am 01:14 AM

Implementing a Caching Layer in a Java Application with Redis

RedisisusedforcachinginJavaapplicationstoimproveperformancebyreducingdatabaseloadandenablingfastdataretrieval.1.InstallRedisusingDocker:dockerrun-d-p6379:6379redis.2.Addspring-boot-starter-data-redisandlettuce-coredependenciesinpom.xml.3.ConfigureRed

Jul 30, 2025 am 03:30 AM

Building RESTful APIs in Java with Jakarta EE

SetupaMaven/GradleprojectwithJAX-RSdependencieslikeJersey;2.CreateaRESTresourceusingannotationssuchas@Pathand@GET;3.ConfiguretheapplicationviaApplicationsubclassorweb.xml;4.AddJacksonforJSONbindingbyincludingjersey-media-json-jackson;5.DeploytoaJakar

Jul 30, 2025 am 03:05 AM

java

How to Manage Dependencies in a Large-Scale Java Project

UseMavenorGradleconsistentlyforreliabledependencymanagementwithclearscopesandcentralizedconfiguration.2.Structurelargeprojectsintomulti-moduleswithaparentPOMorrootprojecttomanageshareddependenciesandenablereusewhileavoidingcycles.3.Strictlycontrolver

Jul 30, 2025 am 03:04 AM

Comparing Java, Kotlin, and Scala for JVM Development

Kotlinoffersthebestbalanceofconcisesyntaxandreadability,reducingboilerplatecomparedtoverboseJava,whileavoidingScala’scomplexityandreadabilityissues.2.JavaandKotlinleadinecosystemintegrationwithfullsupportforframeworkslikeSpringandAndroid,whereasScala

Jul 30, 2025 am 03:00 AM

How to use Java MessageDigest for hashing (MD5, SHA-256)?

To generate hash values using Java, it can be implemented through the MessageDigest class. 1. Get an instance of the specified algorithm, such as MD5 or SHA-256; 2. Call the .update() method to pass in the data to be encrypted; 3. Call the .digest() method to obtain a hash byte array; 4. Convert the byte array into a hexadecimal string for reading; for inputs such as large files, read in chunks and call .update() multiple times; it is recommended to use SHA-256 instead of MD5 or SHA-1 to ensure security.

Jul 30, 2025 am 02:58 AM

java

Implementing Authentication and Authorization in a Java Web App

UseSpringSecurityforrobust,standard-compliantauthenticationandauthorizationinJavawebapplications.2.Implementauthenticationviaform-basedloginorJWTforstatelessAPIs,ensuringpasswordsarehashedwithBCryptandtokensaresecurelymanaged.3.Applyauthorizationusin

Jul 30, 2025 am 02:58 AM

Authentication java web