AdeadlockinJavaoccurswhentwoormorethreadsareblockedforever,eachwaitingforaresourceheldbytheother,typicallyduetocircularwaitcausedbyinconsistentlockordering;thiscanbepreventedbybreakingoneofthefournecessaryconditions—mutualexclusion,holdandwait,nopree

Importjava.ioandjava.net.SocketforI/Oandsocketcommunication.2.CreateaSocketobjecttoconnecttotheserverusinghostnameandport.3.UsePrintWritertosenddataviaoutputstreamandBufferedReadertoreadserverresponsesfrominputstream.4.Usetry-with-resourcestoautomati

This article discusses the mechanism and common misunderstandings of Spring Boot applications for handling non-UTF-8 request encoding. The core lies in understanding the importance of the charset parameter in the HTTP Content-Type header, as well as the default character set processing flow of Spring Boot. By analyzing the garbled code caused by wrong testing methods, the article guides readers how to correctly simulate and test requests for different encodings, and explains that Spring Boot usually does not require complex configurations to achieve compatibility under the premise that the client correctly declares encoding.

The Java design pattern is a reusable solution to common software design problems. 1. The Singleton mode ensures that there is only one instance of a class, which is suitable for database connection pooling or configuration management; 2. The Factory mode decouples object creation, and objects such as payment methods are generated through factory classes; 3. The Observer mode automatically notifies dependent objects, suitable for event-driven systems such as weather updates; 4. The dynamic switching algorithm of Strategy mode such as sorting strategies improves code flexibility. These patterns improve code maintainability and scalability but should avoid overuse.

UseOptional.empty(),Optional.of(),andOptional.ofNullable()tocreateOptionalinstancesdependingonwhetherthevalueisabsent,non-null,orpossiblynull.2.CheckforvaluessafelyusingisPresent()orpreferablyifPresent()toavoiddirectnullchecks.3.Providedefaultswithor

Create a WebSocket server endpoint to define the path using @ServerEndpoint, and handle connections, message reception, closing and errors through @OnOpen, @OnMessage, @OnClose and @OnError; 2. Ensure that javax.websocket-api dependencies are introduced during deployment and automatically registered by the container; 3. The Java client obtains WebSocketContainer through the ContainerProvider, calls connectToServer to connect to the server, and receives messages using @ClientEndpoint annotation class; 4. Use the Session getBasicRe

PrepareyourapplicationbyusingMavenorGradletobuildaJARorWARfile,externalizingconfiguration.2.Chooseadeploymentenvironment:runonbaremetal/VMwithjava-jarandsystemd,deployWARonTomcat,containerizewithDocker,orusecloudplatformslikeHeroku.3.Optionally,setup

Understand JCA core components such as MessageDigest, Cipher, KeyGenerator, SecureRandom, Signature, KeyStore, etc., which implement algorithms through the provider mechanism; 2. Use strong algorithms and parameters such as SHA-256/SHA-512, AES (256-bit key, GCM mode), RSA (2048-bit or above) and SecureRandom; 3. Avoid hard-coded keys, use KeyStore to manage keys, and generate keys through securely derived passwords such as PBKDF2; 4. Disable ECB mode, adopt authentication encryption modes such as GCM, use unique random IVs for each encryption, and clear sensitive ones in time