Summary of second-person interview questions in a company

What coding standards does your company follow for development?

When writing Java code, adhering to good coding conventions is crucial for code readability and maintainability. Here are some more detailed recommendations for Java coding standards:

1. Naming convention :

   • Class names should be nouns or noun phrases, using camel case, with the first letter capitalized, such as CustomerService.

   • Method names should be named after verbs or verb phrases, using camel case, with the first letter lowercase, such as calculateTotalPrice().

   • Variable names should be descriptive, using camelCase, such as itemCount.

   • Constants should generally be written in all caps, with underscores separating words, MAX_VALUEe.g.

   • Package names should be in lowercase letters, with multiple words separated by dots, such as com.example.myproject.

2. Indentation and formatting :

   • Use four spaces for indentation and no tabs.

   • Add spaces around operators, eg x = y + z.

   • Use braces {}to clearly indicate the beginning and end of a block of code, even if the block contains only one line.

3. Note :

   • Use JavaDoc-style comments to describe the role of classes, methods, and fields, including descriptions of parameters and return values.

   • In cases of complex logic or unusual processing, use inline comments to explain the purpose and why of the code.

   • Avoid unnecessary comments, good code should be self-explanatory.

4. Spaces and blank lines :

   • Add spaces around binary operators, eg x = y + z.

   • Add a space after the comma, eg int[] numbers = {1, 2, 3};.

   • Use blank lines to separate different logical blocks to improve readability.

5. Exception handling :

   • Use try-catch blocks to catch and handle exceptions, but avoid catching exceptions without processing them.

   • Try to catch exceptions of specific types rather than generic ones Exception.

6. Guide package :

   • Explicitly import the required packages and avoid using wildcard imports, eg import java.util.*;.

7. Constants :

   • For values ​​that will not change, use finalthe keyword to declare them as constants.

8. Class design :

   • Follow the single responsibility principle and ensure that each class has only one clearly defined responsibility.

   • Follow the open-closed principle, allowing new functions to be added by extending classes instead of modifying existing code.

9. Interfaces and abstract classes :

   • Use interfaces to define contracts and multiple inheritance.

   • Use abstract classes to share common code and provide default implementations.

10. Use appropriate data structures and collections :

    • Choose an appropriate data structure to improve performance, such as using ArrayListor LinkedList.

    • Use generics to increase type safety and avoid type errors at runtime.

These specifications can help you write Java code that is consistent, easy to understand, and maintain. However, please note that different projects and organizations may have their own coding conventions, so it's best to follow the project or team's conventions within a specific project to ensure consistency. At the same time, using a good integrated development environment (IDE) can help you automatically detect and fix code specification issues and improve development efficiency.

Please introduce the databases and cache databases you have come into contact with.

1. Relational database :

   • MySQL : MySQL is an open source relational database management system that I have used in multiple projects. It provides powerful SQL query capabilities with good performance and scalability.

   • PostgreSQL : PostgreSQL is another relational database that I use and it has advanced features like support for complex data types and scalability.

   • Oracle Database : I also have experience with Oracle Database, especially in large enterprise applications where it is widely used.

2. NoSQL database :

   • MongoDB : MongoDB is a document-oriented NoSQL database that I use in projects that require a flexible data model. It stores data using JSON-style documents.

   • Cassandra : Cassandra is a distributed NoSQL database that I use in projects that require high availability and large-scale data processing.

   • Redis : Redis is not only an in-memory cache database, but also a powerful key-value storage system. I use it to cache data and enable high speed data access.

3. Cache database :

   • Memcached : Memcached is a high-performance distributed in-memory object caching system that I use to reduce database load.

   • Redis : In addition to being a database, Redis is also a very powerful caching database that supports rich data structures and complex caching strategies.

   • Ehcache : Ehcache is an open source caching library developed in Java, which I use at the application level for local caching.

These databases and cache databases have their own characteristics and applicable scenarios. I will choose the appropriate database technology based on the needs and performance requirements of the project. I also continue to follow the development of database technology to understand the latest trends and best practices.

How website access ensures data security

Data security is very important to companies and users. Here are some best practices on how to keep your data secure that I actively apply at work:

1. SSL/TLS encryption : I will ensure that websites and applications use SSL/TLS encryption when communicating with users to protect data during transmission.

2. Authentication and Authorization : I will design and implement strong authentication and authorization systems to ensure that only authenticated users have access to sensitive data and functionality.

3. Password Policy : I will encourage users to use strong passwords and implement a password policy, including regular password changes, to prevent unauthorized access.

4. Multi-factor authentication (MFA) : I would consider supporting multi-factor authentication to increase account security, especially for important accounts.

5. Vulnerability Management : I will actively participate in vulnerability scanning and remediation to ensure that potential security vulnerabilities are detected and resolved in a timely manner.

6. Data backup and recovery : I will design reliable data backup and disaster recovery strategies to ensure data availability and integrity.

7. Monitoring and auditing : I will establish a monitoring system to detect abnormal behaviors in a timely manner and record detailed logs for auditing.

8. Employee training : I will participate in safety training to improve my safety awareness and ensure that I have a full understanding of safety issues.

9. Data Privacy : I will comply with relevant data privacy regulations to ensure that user data is properly handled and protected.

10. Security Partner : I will actively work with security experts to draw on their experience and insights to improve security.

In short, I will regard data security as an important responsibility and actively participate in ensuring the security of company and user data. I will continue to learn and adapt to new security challenges to ensure that the company's security measures remain at the highest level. At the same time, I will also work with the team to work on data security.

How do you deliver interface documentation during development?

Delivering interface documentation is an important task in project development, especially when the project involves the development of APIs (application programming interfaces) or services. The following are general steps and best practices for delivering interface documentation:

1. Determine the audience : First, determine who the audience of the interface document is. This may include other developers, front-end developers, mobile app developers, partners, or third-party developers. Understanding the audience helps determine the depth and technical level of the document.

2. Select documentation tool : Select an appropriate documentation tool to create interface documentation. Common documentation tools include Swagger, API Blueprint, Postman, Markdown, etc. Tool selection should take into account the audience and project needs.

3. Describe API endpoints : Describe each API endpoint in detail, including URL, HTTP method (GET, POST, PUT, DELETE, etc.), input parameters, request examples, response formats, and sample responses. Provide clear endpoint naming and description.

4. Parameter description : Provide detailed description for each input parameter, including name, type, whether it is required, default value, etc. This helps other developers use the API correctly.

5. Response description : Describes the response of the API, including status code, structure of response data, field meanings and sample responses. Make sure the structure and data types of the response are clearly visible.

6. Error Handling : Provides error handling information, including possible error status codes, error messages, and sample error responses. Developers need to know how to handle possible error conditions.

7. Authorization and Authentication : If the API requires authentication or authorization, provide instructions and examples so other developers can understand how to obtain access tokens or authorization.

8. Sample code : Sample code is provided for each API endpoint, including examples in different programming languages ​​(such as Python, JavaScript, Java, etc.). This helps other developers use the API more easily.

9. Testing Instructions : Provides testing steps and tools to help other developers test the API. This can include sample requests using Postman or similar tools.

10. Version control : Associate the interface documentation with the project's version control system to ensure that the documentation and code are updated simultaneously. This helps avoid issues with outdated or inconsistent documentation.

11. Review and feedback : Before delivering interface documentation, have team members or audiences review the document to ensure accuracy and clarity. Accept feedback and make necessary changes.

12. Publish and update : Publish the interface documentation to the appropriate location and ensure it is accessible to all relevant people. As the project evolves, the documentation is regularly updated to reflect changes and enhancements to the interface.

13. Training and support : Provide training and support, if needed, to ensure other developers can correctly use the API and understand the documentation.

In summary, delivery interface documentation needs to be clear, detailed, and easy to understand. It should be the primary reference for other developers using the API, so it's important to ensure the quality and accuracy of the documentation.

How does your company structure development, testing, pre-release, and formal environments?

In software development, there are usually multiple environments (such as testing, development, and formal environments), and there will be a clear development and release process to ensure the quality and reliability of the software. The following is an overview of a typical development and release process:

1. Development environment :

   • Development phase : In the development environment, developers write and test new features and code. This phase usually includes unit and integration tests to ensure the basic functionality of the code is working properly.
   • Version control : Developers use version control systems (such as Git) to manage code versions and ensure that code changes are tracked and recorded.

2. Test environment :

   • Integration testing : Once tested in the development environment, the code will be pushed to the testing environment for more comprehensive integration testing. At this stage, not only individual modules are tested, but also the interactions between different components.
   • Automated testing : Automated testing tools are used to execute automated test cases, including unit testing, functional testing, performance testing, etc.
   • Fix and retest : If problems are discovered during testing, the developer fixes them and runs the tests again until the problem is resolved.
   • User Acceptance Testing (UAT) : In a testing environment, user acceptance testing is sometimes performed, performed by end users or product owners to ensure that the software meets business requirements.

3. Pre-release environment :

   • In the test environment, the tested and accepted code is deployed to the pre-release environment through automated processes or manual operations. The staging environment usually simulates the production environment but does not provide services to the outside world.
   • Conduct final performance testing, security scans, and backup verification.

4. Formal environment :

   • Once it is confirmed that there are no problems in the pre-release environment, the code can be deployed to the official production environment.
   • The production environment is usually an environment that provides services to the outside world, so the deployment process must be careful.
   • Monitor and log application performance and health in production environments to promptly identify and resolve potential issues.

5. Continuous improvement :

   • The operations team continuously monitors the production environment, resolves any issues, and ensures system stability and availability.
   • The development team continues to develop new features and improvements into the next development cycle, taking into account user feedback and needs.

It is important to note that this process may vary depending on the size, complexity and requirements of the project. Automation tools and continuous integration/continuous delivery (CI/CD) processes can speed up deployment and testing and improve quality control. At the same time, team collaboration and communication are also key factors to ensure the smooth operation of the process.