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Optimizing Java Docker Images for Smaller Size and Faster Startup

Use smaller basic images such as eclipse-temurin:17-jre-alpine or -slim to reduce volume; 2. Use multi-stage construction to separate compilation and operation environments to avoid throwing the build tools and source code into the final image; 3. Optimize the JAR package itself, remove useless dependencies, enable compression, and consider SpringBoot layered JAR; 4. Enable Class Data Sharing (CDS) to reduce startup time and memory usage; 5. Adjust JVM containerized parameters such as -XX: UseContainerSupport and -XX:MaxRAMPercentage to adapt to container resource limitations; 6. Use GraalVM native mirrors to select scenarios with extremely high startup speed requirements

Jul 29, 2025 am 12:27 AM

java docker

Advanced Exception Handling Strategies in Java

Usespecificexceptionsinsteadofgenericonestoenablepreciseerrorhandlingandimprovedebugging.2.Createcustomexceptionsfordomain-specificerrorstoenhancereadability,enabletargetedcatchblocks,andclarifyAPIcontracts.3.Usetry-with-resourcesforautomaticmanageme

Jul 29, 2025 am 12:16 AM

Java Interoperability with Kotlin: A Seamless Integration

Kotlin can integrate seamlessly with Java because the two run on the JVM and the bytecode is interoperable. The Kotlin compiler automatically generates compatible code to bridge syntax differences and adapts to Java features through language design. 1. Kotlin and Java are compiled into the same JVM bytecode, and classes can be called directly from each other and share classpath; 2. Kotlin uses @JvmOverloads to generate overloaded methods for the default parameters, and the top-level functions are compiled into Java static methods (the class name can be customized through @file:JvmName); 3. Kotlin treats Java types as platform types (such as String!), and needs to manually handle empty security, and supports SAM conversion to La

Jul 29, 2025 am 12:15 AM

Java Authentication and Authorization with JWT

JWT is an open standard for safe transmission of information. In Java, authentication and authorization can be achieved through the JJWT library. 1. Add JJWT API, Impl and Jackson dependencies; 2. Create JwtUtil tool class to generate, parse and verify tokens; 3. Write JwtFilter intercepts requests and verify BearerTokens in Authorization header; 4. Register Filter in SpringBoot to protect the specified path; 5. Provide a login interface to return JWT after verifying the user; 6. The protected interface obtains user identity and roles through parsing the token for access control, and ultimately realizes a stateless and extensible security mechanism, suitable for distributed systems.

Jul 29, 2025 am 12:07 AM

java programming

Reactive Programming in Java with Project Reactor and Spring WebFlux

Responsive programming implements high concurrency, low latency non-blocking services in Java through ProjectReactor and SpringWebFlux. 1. ProjectReactor provides two core types: Mono and Flux, supports declarative processing of asynchronous data flows, and converts, filters and other operations through operator chains; 2. SpringWebFlux is built on Reactor, supports two programming models: annotation and functional. It runs on non-blocking servers such as Netty, and can efficiently handle a large number of concurrent connections; 3. Using WebFlux Reactor can improve the concurrency capability and resource utilization in I/O-intensive scenarios, and naturally supports SSE and WebSo.

Jul 29, 2025 am 12:04 AM

java Reactive programming

Writing Testable Java Code with JUnit 5 and Mockito

Writetestablecodeusingdependencyinjectiontoenableloosecoupling,asseenbyreplacinghard-codeddependencieswithinjectedones;2.UseJUnit5forstructuredtestingwithfeatureslike@BeforeEach,@Test,andassertThrowstoensureclean,readable,andreliabletests;3.Mockexter

Jul 28, 2025 am 03:24 AM

mockito JUnit 5

GraalVM for High-Performance Java Applications

GraalVM changes the performance bottleneck of Java through four key technologies: 1. Native mirroring technology compiles Java applications into local executable files in advance, achieving millisecond startup, lower memory footprint and smaller deployment packages, suitable for Serverless and microservices; 2. High-performance JIT compiler replaces HotSpot's C2, adopts more aggressive optimization algorithms, and improves performance by 20% to 50% in computing-intensive scenarios; 3. Multilingual integration uses Truffle framework to achieve efficient collaboration between Java and JavaScript, Python and other languages, reducing script embedding and hybrid development overhead; 4. Practical applications need to deal with challenges such as long construction time, explicit configuration of reflection, incompatibility of some libraries, and complex debugging.

Jul 28, 2025 am 03:23 AM

java Performance optimization

Using MapStruct for Painless Bean Mapping in Java

MapStruct is a compile-time code generator used to simplify mapping between JavaBeans. 1. It automatically generates implementation classes by defining interfaces to avoid manually writing lengthy set/get mapping code; 2. It has type-safe, no runtime overhead, supports automatic mapping of the same name fields, custom expressions, nested objects and collection mapping; 3. It can be integrated with Spring and uses @Mapper(componentModel="spring") to inject mapper into Springbean; 4. Simple configuration, just introduce mapstruct dependencies and annotationProcessorPaths inserts

Jul 28, 2025 am 03:20 AM

java

Building Interactive UIs with JavaFX

To start building an interactive UI using JavaFX, you must first correctly configure the environment and master the basic UI components, layout, event processing, FXML separation design, CSS style and animation effects. 1. When configuring JavaFX projects, if you use Maven, add javafx-controls dependencies; otherwise, manually configure the SDK and set the --module-path and --add-modules running parameters. 2. Create the main class to inherit Application, override the start() method, define Stage, Scene, control (such as Button, Label) and event response (such as setOnAction), and launch(

Jul 28, 2025 am 03:19 AM

Securing REST APIs in Java using Spring Security

DisableCSRFandsetsessioncreationpolicytoSTATELESSinSecurityConfigtoensurenosessioniscreated;2.UseJWTfortoken-basedauthenticationbygeneratingasignedtokenafterloginandreturningittotheclient;3.ValidatetheJWTinacustomfilter(JwtAuthFilter)thatextractsthet

Jul 28, 2025 am 03:08 AM

java

Mastering Generics in Java for Type-Safe Code

Using generics can improve the type safety and reusability of Java code. The answer is that generics must be used to avoid runtime errors and reduce type conversion; 1. Generics can check type safety at compile time, eliminate cast type conversion, and improve code clarity; 2. Generics can be defined to encapsulate any type, so as to implement type-safe data operations; 3. Use bounded type parameters such as limiting the type scope of generics to ensure type legality; 4. Wildcards ?, ?extendsT and ?superT respectively represent unknown types, upper bound and lower bound limitations, following the PECS principle (producers use extends, consumers use super) to enhance flexibility; 5. Generic methods can define type parameters independently of class, support

Jul 28, 2025 am 02:59 AM

A Comprehensive Look at Java I/O and NIO.2

FormodernfileI/OinJava,useNIO.2(java.nio.file)asitprovidesamoreintuitive,feature-rich,andsaferAPIcomparedtotraditionalI/O;2.UsetraditionalI/Oonlyforlegacycodeorsimplestreamoperations,asitisblockingandlessscalable;3.UseNIOwithchannelsandselectorsforhi

Jul 28, 2025 am 02:47 AM

nio.2 Java I/O

Java Persistence with JPA and Hibernate: Best Practices and Patterns

Keep the entity class simple and implement equals/hashCode based on ID only; 2. Use lazy loading reasonably and cooperate with @EntityGraph or DTO to avoid N 1 queries; 3. Use @Transactional to manage transactions, read operation mark readOnly=true; 4. Use @Version to optimistically lock to prevent concurrent updates from being lost; 5. Cascade operations need to clearly specify the type to avoid abuse of CascadeType.ALL. Following these practices can significantly improve the performance and maintainability of JPA Hibernate applications.

Jul 28, 2025 am 02:46 AM

java

what is garbage collection in java

Java's garbage collection mechanism automatically manages memory, identifying and freeing objects that are no longer in use to avoid memory leaks. 1. Use accessibility analysis to determine whether the object is garbage; 2. Common recyclers include SerialGC, ParallelGC, CMS, G1, ZGC and Shenandoah; 3. Developers can optimize GC performance by reasonably setting the heap size, avoiding memory leaks, optimizing object life cycle, monitoring GC behavior, etc.

Jul 28, 2025 am 02:45 AM

java Garbage collection