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Java Application Security Testing (SAST, DAST)

Java application security testing requires two methods: static analysis (SAST) and dynamic analysis (DAST). 1. SAST is used for source code or bytecode analysis when the code is not running. Tools such as SonarQube, Checkmarx, etc. should be integrated into the CI/CD process as soon as possible, pay attention to high-risk vulnerabilities such as SQL injection and XSS, and pay attention to false positive handling; 2. DAST simulates attacks when the application runs, suitable for testing or pre-release environments. Tools such as OWASPZAP, BurpSuitePro, etc. can find authentication defects, overpriced access and logical vulnerabilities, and pay attention to the availability of the test environment and system pressure; 3. The two are used complementary, SAST is used in the development stage, DAST is used for post-deployment testing, and regularly

Jul 22, 2025 am 03:44 AM

java Safety test

java regular expression example

Java regular expressions are used for string matching, extraction, replacement and segmentation operations. 1. When matching the email address, verify the format legitimacy through regular expressions, such as using [a-zA-Z0-9._% -] @[a-zA-Z0-9.-] \\.[a-zA-Z]{2,}; 2. When extracting the phone number, use \\d{3}-\\d{3}-\\d{4} and combine Pattern with Matcher class to find matches; 3. Replace sensitive words can be replaced("Junk|Poor","\\*\\*\\*\\*") to achieve content filtering; 4. When splitting strings, you can divide them by commas or spaces.

Jul 22, 2025 am 03:41 AM

What is the Java Native Interface (JNI)?

JNI (JavaNativeInterface) is a framework for allowing Java code running in the JVM to interact with applications and libraries written in other languages such as C, C or assembly. Its core uses include: 1. Improve performance key parts; 2. Integrate legacy systems; 3. Achieve hardware access; 4. Utilize platform-specific functions. When using it, you need to mark the native method and link it to the shared library. When called, the JVM will look for the corresponding function to execute, and at the same time operate the Java object through the JNIEnv pointer. Common problems include manual cleaning of memory management, validity of JNIEnv in threads, exception checking and naming specifications, and debugging requires combining tools such as jdb and GDB.

Jul 22, 2025 am 03:38 AM

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Optimizing Java Application Deployment on Kubernetes

Deploying Java applications to Kubernetes requires optimization of JVM parameters, image construction, health checks and scaling strategies. 1. Adjust the JVM parameters to adapt to the container environment, enable UseContainerSupport and set the heap size reasonably; 2. Optimize the image construction process, adopt multi-stage construction and lightweight basic images; 3. Properly configure Readiness/LivenessProbe to avoid false restarts due to slow startup; 4. Use HPA to achieve automatic scaling based on CPU or custom indicators, and set appropriate number of copies and indicator thresholds.

Jul 22, 2025 am 03:38 AM

how to write to a file in java

Common methods of writing files in Java include: 1. Use FileWriter to simply write text files, suitable for a small amount of character data, pay attention to using try-with-resources and overwrite/append mode; 2. Use BufferedWriter to improve writing efficiency, suitable for multi-line text content, and support line-by-line writing and loop processing; 3. Use FileOutputStream to write binary files, operate byte streams, suitable for non-text data such as pictures and audio; 4. Use PrintWriter to format writing more conveniently, support println and printf, suitable for log and report output. Selecting the right method requires consideration of data type, performance requirements and write mode management

Jul 22, 2025 am 03:33 AM

Java Microservices Deployment Strategies on Kubernetes

When deploying Java microservices to Kubernetes, you should choose the appropriate strategy based on business needs and resource conditions. 1. RollingUpdate is the most commonly used strategy. By gradually replacing old pods, it ensures that the service is not interrupted, which is suitable for most scenarios; 2. Blue-GreenDeployment achieves zero downtime through two sets of environment switching, which is suitable for highly available systems but requires double resources; 3. CanaryRelease realizes grayscale release, gradually verifying the stability of the new version, which is suitable for systems with large impact; 4. Recreate strategy is simple but has the risk of interruption, which is suitable for testing environments or scenarios where downtime is acceptable. Each strategy has its own advantages and disadvantages. It is recommended to use the first three in the production environment to ensure stability and

Jul 22, 2025 am 03:31 AM

Java Security Frameworks Comparison (Spring Security, Apache Shiro)

SpringSecurity is more suitable for Spring projects, especially SpringBoot; Shiro is lighter and suitable for non-Spring or small projects. 1. Usage scenarios: SpringSecurity is suitable for modern Spring ecological applications, with tight integration and rich features; Shiro is lighter and suitable for traditional JavaSE or small web applications. 2. Authentication and authorization mechanism: SpringSecurity is based on a filter chain, supports multiple authentication methods and provides annotation control method permissions; Shiro provides Subject interface and Realm customization, and has flexible configuration but requires manual settings of URL permission rules. 3. Configuration difficulty: SpringSec

Jul 22, 2025 am 03:23 AM

Java Distributed Caching with Redis and Hazelcast

Redis is suitable for centralized cache and persistent storage, supports multiple data structures and high-availability architectures, and is suitable for global high-frequency data; Hazelcast is a lightweight distributed cache that supports local distributed hybrid scenarios, suitable for temporary and reconstructible data; the two can be used in combination, Redis handles global data, and Hazelcast manages local distributed data; at the same time, cache penetration, avalanche, and breakdown problems need to be handled.

Jul 22, 2025 am 03:17 AM

java redis

Java Security for Cross-Site Scripting (XSS) Prevention

The core of preventing XSS vulnerabilities is to process user input and correctly output encoding. 1. Input filtering: Use whitelists to allow specific HTML tags, reject other content, avoid completely disabling HTML escaping, and do not rely on front-end verification. Java can clean up input with OWASP JavaEncoder or Jsoup. 2. Output encoding: Use HTML, JavaScript or URL encoding according to the context, Spring and Thymeleaf also provide automatic escape function. 3. Use CSP: Restrict script sources through HTTP response headers as the last line of defense. Maintaining good coding habits can effectively avoid XSS attacks.

Jul 22, 2025 am 03:08 AM

Java Performance Monitoring with Prometheus

To monitor Java application performance, you can expose metrics through Micrometer or Prometheus Java client, configure Prometheus crawl and combine Grafana visualization and Alertmanager alerts. 1. Introduce Micrometer dependencies and configure SpringBoot exposure/actuator/prometheus interface; 2. Add Java application crawling targets in prometheus.yml and ensure that the network is reachable; 3. Use Grafana import template to achieve visual display, and configure key indicator alert rules such as memory through Alertmanager; 4. Pay attention to avoid duplication of indicators and checking and crawling

Jul 22, 2025 am 03:07 AM

How to implement a WebSocket server in Java?

ToimplementaWebSocketserverinJava,useJSR356withJavaEEorTyrusinstandalonesetups.1)AddTyrusdependenciesviaMavenifnotusingJavaEE.2)Createanendpointclassannotatedwith@ServerEndpointtohandlemessagesandlifecycleevents.3)LaunchtheserverusingTyrusbyspecifyin

Jul 22, 2025 am 02:55 AM

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how to compare strings in java equals vs ==

Comparing string content in Java should use equals() instead of ==. ==Compare whether the reference is the same. For example, Stringa and Stringc point to different objects, return false; equals() is used to determine whether the content is consistent, regardless of whether the object is the same; it is recommended to use "abc".equals(str) to avoid null pointers; string constant pooling makes the same literals possible to point to the same object, but cannot rely on this behavior; == can be used to determine whether it is a specific object or as a preliminary judgment for performance optimization. In short, equals() must be used to determine whether the content of the string is equal.

Jul 22, 2025 am 02:44 AM

Advanced Java Stream API Parallel Processing

Parallel flows are not necessarily faster because of the overhead of task splitting, coordination, and merging. Suitable situations for using parallel streams include calculation-intensive operations (such as image processing, numerical calculations) and data sources with strong detachability (such as ArrayList), and run in a multi-core CPU environment; unsuitable situations include small data volume, lightweight operations, or involvement of shared resources. Correct use of parallel flow requires ensuring thread safety, controlling parallelism, avoiding IO operations, and conducting actual tests and analysis performance. By default, all parallel streams share a ForkJoinPool, which may cause thread starvation and can be resolved by custom thread pooling.

Jul 22, 2025 am 02:37 AM

Understanding Java ConcurrentHashMap Internals

ConcurrentHashMap achieves thread safety through segmented locks (JDK1.7) and CAS synchronized (JDK1.8). 1. In JDK1.7, a segmented lock mechanism is adopted, with 16 segments by default, each locking, which improves concurrent writing capabilities, but cannot expand the number of segments; 2. JDK1.8 uses a Node array structure instead, combining CAS and synchronized to lock a single node to improve memory efficiency and concurrency performance; 3. The put method prioritizes CAS insertion, and locking is handled during conflicts; 4. The get method has no locks and relies on volatile to ensure visibility; 5. The size method returns an approximation, and requires additional means to obtain accuracy

Jul 22, 2025 am 02:28 AM