Engineering With Java: Digest #31

Curated and Hand Picked Java and Spring Blogs

In this Engineering With Java newsletter edition, we have hand-picked some interesting Java and Spring articles worth reading. Topics include spring boot actuator, Quarkus rest API, code analysis, infinite loops, performance tuning, Websocket API, file locking, etc.

Four Easy Ways to Analyze Your Java and Kotlin Code for Security Problems

This article offers practical methods to enhance the security of Java and Kotlin applications. Here’s a summary of the key points:

1. Static Code Analysis: Utilize tools that examine code without executing it. These tools can identify common vulnerabilities and coding errors that could lead to security issues.

2. Dynamic Analysis: This involves testing application while it is running. By monitoring the application’s behavior, we can detect vulnerabilities that manifest only during execution.

3. Dependency Scanning: Analyze the libraries and frameworks our code depends on. Vulnerabilities in third-party components can pose significant risks, so keeping these dependencies up-to-date and scanning them for known issues is crucial.

4. Code Reviews: Regular peer reviews can help spot security issues that automated tools might miss. Human reviewers can provide insights and identify potential problems based on experience and context.

Implementing these methods can significantly improve the security posture of Java and Kotlin applications by catching and addressing potential vulnerabilities early in the development lifecycle.

https://foojay.io/today/four-easy-ways-to-analyze-your-java-and-kotlin-code-for-security-problems/

Avoiding and Understanding Infinite Loops in Java

This article provides insights into how infinite loops occur in Java and strategies to avoid them. Here's a summary:

1. Understanding Infinite Loops: An infinite loop is a loop that continues to execute indefinitely because the terminating condition is never met. This usually results from logical errors in the loop condition or incorrect updates within the loop.

2. Common Causes:

   • Faulty Loop Conditions: Conditions that are always true or fail to change appropriately can cause infinite loops.

   • Incorrect Increment/Decrement: Failing to update the loop variable correctly can prevent the loop from reaching its termination condition.

   • Logical Errors: Errors in the logic used to determine when the loop should end can also lead to infinite loops.

3. Avoiding Infinite Loops:

   • Careful Condition Design: Ensure that loop conditions are properly defined and will eventually become false.

   • Proper Variable Updates: Verify that loop variables are updated correctly on each iteration to ensure progress towards the loop's termination.

   • Testing and Debugging: Use debugging tools and techniques to test loop behavior and catch potential infinite loops early in development.

4. Handling Infinite Loops:

   • Break Statements: Use break statements to exit a loop if certain conditions are met.

   • Timeouts: Implement timeouts or maximum iteration limits to prevent loops from running indefinitely.

By understanding these concepts and applying best practices, developers can avoid and manage infinite loops effectively in their Java programs.

https://medium.com/@AlexanderObregon/avoiding-and-understanding-infinite-loops-in-java-b3a294d11a47?source=rss-4f9731d3205------2

Java Performance Tuning: Adjusting GC Threads for Optimal Results

This article focuses on optimizing Java application performance through garbage collection (GC) thread adjustments. Here's a summary:

1. GC Threads and Performance: Garbage collection is a key component of Java's memory management, and the number of threads used for GC can significantly impact performance. Properly tuning GC threads can enhance application responsiveness and reduce latency.

2. Default Settings: Java's default GC thread settings are often adequate for general use, but specific applications with high memory demands or real-time requirements may benefit from customization.

3. Tuning GC Threads:

   • -XX:ParallelGCThreads: This flag controls the number of threads used during parallel garbage collection. Increasing the number of threads can improve GC performance but may also increase CPU usage.

   • -XX:ConcGCThreads: This flag adjusts the number of threads for concurrent garbage collection phases, impacting the performance of concurrent marking and cleanup.

4. Considerations for Tuning:

   • Application Workload: The optimal number of GC threads depends on the application’s workload and memory usage patterns. Profiling and testing are essential to determine the best configuration.

   • CPU and Memory Resources: Ensure that the system has sufficient CPU and memory resources to support additional GC threads without adversely affecting overall application performance.

5. Monitoring and Adjustment: Continuously monitor GC performance and application behavior to fine-tune the number of GC threads. Tools like JVM monitoring and profiling tools can help assess the impact of changes and guide further adjustments.

By carefully tuning GC threads, developers can optimize garbage collection performance, leading to more efficient memory management and improved application responsiveness.

https://dzone.com/articles/java-performance-tuning-adjusting-gc-threads

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Documenting a Java WebSocket API Using Smart-Doc

This article discusses how to create and manage API documentation for Java WebSocket applications using the Smart Doc tool. Here’s a summary:

1. Purpose of Smart Doc: Smart Doc is a tool designed to generate documentation for Java APIs, including WebSocket APIs. It helps in creating clear, accurate, and comprehensive documentation for developers working with WebSocket connections in Java applications.

2. Features of Smart Doc:

   • Automatic Documentation Generation: Smart Doc can automatically generate documentation from Java code annotations, making it easier to maintain up-to-date API documentation.

   • Support for WebSocket APIs: It supports the specific needs of WebSocket APIs, allowing developers to document WebSocket endpoints, messages, and connection details.

3. How to Use Smart Doc:

   • Annotations: Use Smart Doc annotations in Java code to mark up WebSocket API elements such as endpoints, message types, and methods.

   • Configuration: Configure Smart Doc to specify documentation output formats and customize the generated content according to needs.

   • Generation: Run Smart Doc to generate the documentation files, which can then be reviewed, published, or integrated into development workflows.

4. Benefits:

   • Improves Documentation Accuracy: Automates the process of keeping API documentation in sync with the codebase.

   • Facilitates Developer Understanding: Provides clear and structured documentation, making it easier for developers to understand and use WebSocket APIs.

5. Integration: Smart Doc can be integrated into existing build processes and documentation systems, allowing for seamless updates and maintenance of API documentation.

By using Smart Doc, developers can streamline the process of generating and maintaining documentation for Java WebSocket APIs, enhancing the clarity and usability of their WebSocket services.

https://dzone.com/articles/generate-java-websocket-api-documentation-using-smart-doc

Beyond Java Serialization: Exploring Alternative Approaches

This article explores various methods and technologies for object serialization in Java, beyond the traditional Java serialization mechanism. Here’s a summary:

1. Limitations of Java Serialization:

   • Performance Issues: Java's default serialization can be slow and inefficient, especially for large objects or complex object graphs.

   • Security Risks: Java serialization can expose applications to security vulnerabilities, such as deserialization attacks.

   • Compatibility Problems: Serialized data might not be backward-compatible with different versions of a class.

2. Alternative Serialization Approaches:

   • JSON (JavaScript Object Notation): A lightweight, human-readable format that is widely used for data interchange. Libraries like Jackson or Gson provide robust support for JSON serialization and deserialization.

   • XML (eXtensible Markup Language): An older format that is verbose but offers flexibility in defining data structures. Libraries such as JAXB (Java Architecture for XML Binding) facilitate XML serialization.

   • Protocol Buffers: A language-neutral, platform-neutral, extensible mechanism developed by Google for serializing structured data. It offers efficient and compact serialization compared to Java’s default mechanism.

   • Avro: Developed by Apache, Avro is a binary serialization format that provides compact, fast, and schema-evolving serialization. It is often used in data-intensive applications.

   • MessagePack: A binary format that aims to be more efficient and compact than JSON while maintaining its simplicity and ease of use.

3. Choosing the Right Approach:

   • Use Case Considerations: The choice of serialization method depends on factors such as performance requirements, data complexity, and compatibility needs.

   • Library and Framework Support: Evaluate the libraries and frameworks available for each serialization method to ensure they meet application’s needs.

4. Advantages of Alternatives:

   • Improved Performance: Many alternatives offer better performance and lower overhead compared to Java’s built-in serialization.

   • Enhanced Security: Some formats are less prone to security vulnerabilities and offer better mechanisms for securing serialized data.

   • Better Flexibility and Compatibility: Alternatives often provide more flexibility in handling schema evolution and compatibility issues.

By exploring and adopting these alternative serialization approaches, developers can overcome the limitations of Java’s default serialization and choose solutions that better meet the needs of their applications.

https://www.javacodegeeks.com/2024/08/beyond-java-serialization-exploring-alternative-approaches.html

How to lock a File before writing in Java?

This article on Java67 explains how to manage file access in Java by using file locks to prevent simultaneous writes to a file. Here’s a summary:

1. Purpose of File Locking:

   • Prevent Concurrent Access: File locking is used to ensure that only one process or thread can write to a file at a time, preventing data corruption and inconsistencies.

2. Using FileChannel for Locking:

   • Obtain a FileChannel: To lock a file, you first need to obtain a FileChannel object by opening a file using a FileInputStream or FileOutputStream.

   • Acquire a Lock: Use the FileChannel’s lock() method to acquire an exclusive lock on the file. This method can block until the lock is available or fail if another process holds the lock.

   • Handle Exceptions: Proper exception handling is crucial, as file locking operations can throw IOException.

3. Code Example:

   • The article provides a code snippet demonstrating how to acquire and release a file lock using FileChannel. The lock is acquired before writing to the file and released after the operation is complete.

4. Releasing the Lock:

   • Release Resources: It is essential to release the file lock and close the FileChannel to avoid resource leaks. This is typically done in a finally block to ensure that the resources are released even if an exception occurs.

5. Alternative Approaches:

   • java.nio.file Package: For newer Java versions, the java.nio.file package provides additional utilities for file locking and management, offering more robust and flexible file operations.

By using file locks, developers can manage concurrent access to files, ensuring data integrity and preventing conflicts in file writing operations.

http://www.java67.com/2018/01/how-to-lock-file-before-writing-in-java.html

Changing Spring Boot Properties at Runtime

This article discusses techniques for modifying Spring Boot application properties without restarting the application. Here's a summary:

1. Dynamic Property Changes: Changing properties at runtime allows applications to adapt to new configurations or external conditions without downtime.

2. Using Spring Boot Actuator:

   • Actuator Endpoints: Spring Boot Actuator provides management endpoints that can be used to view and manage application properties. The /actuator/env endpoint can be particularly useful for inspecting current environment properties.

   • Endpoint Configuration: To use these endpoints, include the spring-boot-starter-actuator dependency and configure the endpoints in application.properties or application.yml file.

3. Spring Cloud Config:

   • External Configuration: Spring Cloud Config enables externalized configuration management, allowing you to update configuration properties stored in a central configuration server. This approach supports live updates across multiple instances of an application.

   • Refresh Scope: The @RefreshScope annotation allows specific beans to be refreshed when configuration changes are detected, making it possible to apply new property values dynamically.

4. Custom Solutions:

   • Custom Endpoints: Implement custom endpoints or controllers to handle property updates. This approach requires manual management and security considerations but offers flexibility in how properties are updated and applied.

   • Configuration Reloading: Use mechanisms to reload configurations or restart specific components within the application when properties change.

5. Considerations:

   • Performance Impact: Dynamically changing properties may affect application performance or stability. Test thoroughly to ensure that runtime changes do not introduce issues.

   • Security: Ensure that dynamic property management endpoints are secured to prevent unauthorized changes.

By leveraging Spring Boot Actuator, Spring Cloud Config, or custom solutions, developers can manage and update application properties at runtime, improving flexibility and responsiveness in their applications.

https://www.baeldung.com/spring-boot-properties-dynamic-update

How to Consume REST API in Quarkus

This article provides a guide on interacting with REST APIs using the Quarkus framework. Here’s a summary:

1. Setup Dependencies:

   • Add quarkus-rest-client dependency to Maven or Gradle project to enable REST client functionality.

2. Create REST Client Interface:

   • Define an interface annotated with @RegisterRestClient. Use JAX-RS annotations (e.g., @GET, @POST) to specify API endpoints and HTTP methods.

3. Configure the Client:

   • Set the base URL for the REST API in application.properties with the quarkus.rest-client."client-name".url property.

   • Inject the REST client into Quarkus application using @Inject.

4. Use the Client:

   • Call methods on the REST client interface to interact with the API. Handle responses and exceptions as needed.

5. Error Handling:

   • Implement error handling to manage API errors and exceptions.

   • Utilize Quarkus logging to monitor API interactions.

By following these steps, developers can efficiently consume REST APIs in Quarkus, leveraging its features for effective Java application development.

https://www.baeldung.com/java-quarkus-consume-rest-api

Custom Spring Boot Actuator Endpoint

This article explains how to create custom management endpoints in a Spring Boot application using the Actuator framework. Here’s a summary:

1. Introduction to Spring Boot Actuator:

   • Spring Boot Actuator provides built-in endpoints for managing and monitoring applications. These include health checks, metrics, and environment details.

2. Creating a Custom Endpoint:

   • Define the Endpoint: Create a new class annotated with @Component and extend AbstractEndpoint or Endpoint. Use @Endpoint annotation to mark it as a custom endpoint.

   • Implement Endpoint Logic: Override the necessary methods to implement the logic for custom endpoint. For example, you can return custom metrics, application status, or other useful information.

3. Register the Endpoint:

   • Configuration: Register custom endpoint in the application.properties or application.yml if needed. Ensure it is included in the actuator’s endpoint exposure settings.

4. Accessing the Custom Endpoint:

   • Test the Endpoint: Once implemented, you can access custom endpoint via HTTP or JMX (depending on the configuration) to retrieve the information it provides.

5. Security Considerations:

   • Secure Endpoints: Configure security settings to protect custom endpoints from unauthorized access, ensuring that sensitive information is not exposed.

By following these steps, you can extend Spring Boot Actuator with custom endpoints to provide tailored management and monitoring features for applications.

https://vladmihalcea.com/custom-spring-boot-actuator-endpoint/