. . .

LD refers to Little Dinosaur.

Self - Introduction

requirements:

Prepare a fluent self-introduction and a detailed summary of work/project experience.
Familiarize yourself thoroughly with your resume.Be ready to elaborate on your roles, achievements, and
technologies/tools you used.

Hey there! I’m Leo Hu.

I’ve been working as a Java fullstack developer for over ten years now, and I have experience building scalable,high-performance backend services and dynamic frontend web pages to solve real business problems.

I’m good at Java, JavaScript, Spring Boot and React. I used them to create many RESTful APIs. These APIs have detailed documentation, and I used these APIs to make backend services and frontend applications communicate with each other, and also make many different micro services communicate with each other in a distributed environment.

In backend development:
- For security, I use Spring Security, OAuth2, JWT to implement authentication and authorization, to make sure
  everything is secure.
- For data processing, I also work with Apache / əˈpætʃi / Kafka for real-time data processing, to build
  event-driven architectures that handle high-throughput data streams and scalable messaging systems.
- For database, I mainly use MySQL and MongoDB and redis, I’ve got plenty of experience with Hibernate and JPA for
  data persistence. (I design complex schemas, optimize queries, and ensure data integrity)
- For cloud platforms, I worked with many AWS services. I use EC2(Elastic Compute Cloud) to deploy and manage virtual servers, ECS(Elastic Container Service亚麻自带的类似k8s的东西一般给小公司用, 还有个EKS是兼容k8s的容器编排管理服务, 大点的公司一般用EKS) to orchestrate / ˈɔːrkɪstreɪt / Microservices in containers,RDS to handle relational databases, S3 to handle scalable storage, I use CloudWatch to track performance, monitor logs, metrics, and system health.
In frontend development:
- for state management, I use Redux for complicated state management, and use useReducer + useContext for simpler state management.
- for responsive UI, I use Material UI to provide a consistent user experience no matter what device or browser people use, they’ll have a similar experience.
- for testing, I use Jest for unit testing and React Testing Library for behavior driven testing.

Work/Project Summary

requirements: Prepare 1-2 examples of past projects or jobs where you made a significant impact. Use the STAR
method (Situation, Task, Action, Result) to structure your responses. DO NOT READ, we can tell!

and next let me talk about my work experience:
Project 1:
- Situation: First, let me talk about the company I’m currently working for. its name is Costco, it’s a retail and e-commerce company,
  - I’m a senior java fullstack developer there.
  - I was in a e-commerce team.
  - the project was a e-commerce platform.
  - I’m mainly responsible for developing and maintaining the core modules, like retail data processing and system integration and optimizing the performance and handling some business logic like: e-commerce platform, order system, payment system, delivery system and so on.
  - Because the number of transactions was growing very fast, but their old systems couldn’t keep up with new features and increasing user activity, so we needed a some stronger systems.
- Task: So I used Java/Spring Boot/kafka/redis/PostgreSQL/aws services/kubernetes to build a more scalable backend architecture and developed some microservices, and use JavaScript/React to build some responsive single-page application, and optimize the database-related parts and enhance security.
- Action(unnecessary, should skip): So I had to take some actions to finish my task. so First,(根据从处理数据一点点到部署的顺序记忆)
  - to handle scalability, I used springboot to developed a modular microservices architecture and designed plenty of RESTful APIs. Each service handled a specific function, like user management, poll management, and data analysis.
  - to handle security, I used Spring Security and OAuth2 for authentication and authorization.
  - to handle data processing, I used Kafka to make data analysis much faster.
  - to handle database, I used Redis caching to reduce database load and speed up responses. I also optimized database queries by adding indexes, removing redundant joins.
  - to handle storage, I integrated AWS RDS to enhance data management. , integrating third-party analysis tools.
  - to handle deployment, I used Docker and Kubernetes to handle it.
- Result(optional): as the result, The new microservices architecture made the system more flexible and easier to maintain. and the e-commerce platform also became more scalable, and its frontend also became more efficient, beautiful and easy to use, like: the web page loading time was reduced by 30%, our API response times improved by 30%, our system handled 20% more daily transactions, and user engagement went up by 25%.
Before that, I spent three years at Netflix, where I built high-throughput, low-latency backend services to support real-time content recommendation and consumer engagement across platforms. and I spent two years at Adobe, I developed backend microservices using Spring Boot to support video conferencing, chat, and collaboration features. And I’ve also got experience in the financial industry directly, when I was at Robinhood, I developed real-time market data pipelines, designed secure APIs for stock platform.
that’s pretty much what I did, I read very carefully about this job description, I think this position is a perfect match for me .

questions about your resume

Costco
- Costco has an office on Morena Blvd /mɔːˈreɪnə ˈblʌvd/. in San Diego /sæn diˈeɪɡəʊ/.
- …

Netflix

Yeah, they’ve got an office in Midtown Manhattan /mæn'hæt(ə)n/, New York City.
I was part of the recommendation team.
the project was a consumer engagement platform.
Netflix was doing research to predict what users will like based on their age and their gender and some kinds of their personal information.
- And we also used a large model to make these predictions. For example we use their location data subscribe information and watch history as input and then the model will decide what should be shown to the user.
And my job was to develop some services to handle the user data in real time. We wanted to make sure the personalized content immediately whenever a user’s actions changed.
We also developed a microservices architecture to handle millions of users and tools like Kubernetes to ensure its scalability.

Adobe

Their main office is in San Jose /sænhəu'zei/, California.
(optional) i was remote in Adobe,
I was in a Collaboration Services Team.
the project was a Collaboration Platform.
we developed backend microservices using Spring Boot to support video conferencing, chat, and collaboration features.
- like Users can start or join scheduled video meetings with a single click,
- and Users can send direct messages or participate in group chats while in a meeting
- During a video chat, users can edit documents together at the same time using the collaboration features
My main responsibility was designing and building RESTful APIs to handle session management, user presence, messaging, and collaboration events.

Robinhood

They have a tech team in Denver /ˈdenvər/, Colorado /ˌkɑːləˈrædoʊ; /
I was in an online trading team.
the project was a stock trading platform.
We used Kafka to handle the data streams, and I focused on making sure the pipeline was low-latency and reliable, because any delay could affect trading decisions.
I also helped design secure APIs for the trading platform, like for showing real-time prices, historical charts, and user portfolio data.
and for a financial company, Security and stability were a big deal, so we built in access control, authentication, rate limiting, and monitoring to make sure the system ran smoothly.

fulltime job BQs

~ 宁可保守表达，也不要踩雷。很多时候，过于强调自己的“领导力”或“功劳”反而让 HM 产生反感。要多用“we”，少用“我一个人搞定”；强调合作，而不是独自英雄主义。
~ 别一兴奋就一直说。面试是双向交流，不是演讲。说多了容易暴露短板、绕远路，反而让人觉得你控制力不足。
~ 倾听，有时候比表达更关键。真正成熟的沟通，往往体现在你能否听懂对方的关注点，并围绕它精准回应。所以，当我们准备 Behavioral、HM 面或系统设计时，不妨更多地从“对方角度”出发，理解他们在乎什么、担心什么、欣赏什么，而不是一味展示自己。

下面是一些我碰到的面试问题：

~ Tell me about a time you worked on a team project.
~ If your boss tell you 1+1=3 and ask you to continue working on it. What would you do?
~ Describe a situation where you had to work with a difficult teammate.
.
~ How do you handle disagreements in a team?
.google и
~ Give an example of how you contributed to a team’s success.
~ Tell me about a difficult problem you faced and how you solved it.
-baidu 1point3acres
~ How do you prioritize multiple tasks when deadlines are tight?
~ Tell me about a time you worked under significant pressure.. 1point 3 acres
~ Describe a time when you led a project or initiative.
~ How do you handle taking on responsibilities outside your job description?
~ What are you most proud of professionally?
~ Tell me about a time when you set and achieved a challenging goal.

Pilot Training Questions

How to Answer a Corp-to-Corp Vendor’s Call?

Vendor: May I talk with ZhangSan?

You: Yes, this is ZhangSan. What can I do for you ?

Vendor: Hi ZhangSan, how are you today?

You: I’m good, thanks! How about you?

Vendor: I’m [Name] from [Company]. Are you looking for a Java Developer/Full Stack Developer position?

You: Yes! May I know if your position is a Corp to Corp (C2C) position?

(If Vendor says “No, it’s W2”)

You: Does your company have any Corp to Corp opportunities?
• If “No” → End the conversation: I have an employer and I’m only looking for C2C opportunities. Thanks for your time!
• If “Yes” → Continue the discussion

You: Is this position remote or onsite?

Vendor: It’s onsite.

You: May I know the location?

(If the location is your current city)

You: I’m local to that area.

(If relocation is needed)

You: I have no problem with relocation.

Vendor: What visa are you on?

You: [Answer according to mock discussions]

Vendor: What is your expected rate?

You: The rate needs to be discussed with my employer.

Vendor: Understood. I’ll send you the job description/RTR over email.

(If Vendor does not mention email, you ask first)

You: May I know if you have sent an email to my email ID?

(If received, confirm)

You: I received it. I will reply shortly. I will also provide my employer’s phone number and email ID, so please discuss the rate and send rate confirmation to them.

(If not received, request it)

You: Please send it over, and I will reply once I receive it. I will also provide my employer’s phone number and email ID for rate discussion.

Email Follow-Up:
• If they need a Bench Sales Contact, you can provide:
This is my bench sales contact, Edward.
• Phone: 2017246910
• Email: jade@pilottechnologies.net

Leetcode

Arrays
- Two sum: https://leetcode.com/problems/two-sum/description/
- Contains Duplicate: https://leetcode.com/problems/contains-duplicate/description/
- Group Anagram: https://leetcode.com/problems/group-anagrams/description/
- Best Time to Buy and Sell Stock: https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/
- Top K Frequent Elements: https://leetcode.com/problems/top-k-frequent-elements/description/
- Longest Consecutive Sequence: https://leetcode.com/problems/longest-consecutive-sequence/description/
Two Pointer
- Valid Palindrome: https://leetcode.com/problems/valid-palindrome/description/
- 3Sum: https://leetcode.com/problems/3sum/description/
Binary Search
- Binary Search: https://leetcode.com/problems/binary-search/description/
- Search in Rotated Sorted Array: https://leetcode.com/problems/search-in-rotated-sorted-array/description/
- Koko Eating Bananas: https://leetcode.com/problems/koko-eating-bananas/description/
Sliding Window
- Longest Substring Without Repeating
  Characters: https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
Linked List
- Reverse Linked List: https://leetcode.com/problems/reverse-linked-list/description/
- Merge Two Sorted Lists: https://leetcode.com/problems/merge-two-sorted-lists/description/
- Linked List Cycle: https://leetcode.com/problems/linked-list-cycle/description/
- Copy List with Random Pointer: https://leetcode.com/problems/copy-list-with-random-pointer/description/
Stack & Queue
- Valid Parentheses: https://leetcode.com/problems/valid-parentheses/description/
- Min Stack: https://leetcode.com/problems/min-stack/description/
- Implement Queue using Stacks: https://leetcode.com/problems/implement-queue-using-stacks/description/
DFS & BFS
- Number of Islands: https://leetcode.com/problems/number-of-islands/description/

Rest API

User Info
- Given URL: https://jsonplaceholder.typicode.com/users
- You need to write a REST api to call the given URL and return a user with its “name, username, zipcode”
- for example, if user id is 1, you should return a JSON file with username “Bret”, email “Sincere@april.biz” and
  zipcode “92998-3874”
  - HINT: use “Rest Template”
- Result: OPEN a webbrowser and enter: http://localhost:8080/user/1 should return the correct result.
- Follow-up: id only 1-10, how to handle /user/11 → print in the page “Invalid ID”
- Solution
Movie
- https://jsonmock.hackerrank.com/api/movies/search/?Title=waterworld
- GIVEN Above URL. Write a MVC with rest api to fetch this URL and then create new rest APIs to:
  - Show all movies
  - Show all movies sort by year
  - Fetch a particular movie based on its imdbID.
  - Hint: have multiple pages
- Solutions
  - look at this URL date, it has multiple pages, each page has 10 movies, we need to fetch all pages to get a
    full list of movies and then filter to find the particular movie by imdbID
  - each movie has Title, Year, imdbID three fields, we need to create a model to match them
  - need org.json.simple to parse the json object from the given URL
Build a POST API /greetings with below requirements
- Create a POST API /greetings
- INPUT – json array: [{“name”:”john doe”, “work”: “engineer”}, {“name”:”jane who”, “work”: “manager”}]
- OUTPUT - json: {“data”: [“Hello john the engineer”, “Hello jane the manager”], “timestamp”: “$
  {requested_timestamp}”
- Use postman to call the API and pass input, it should return the correct response.

Knowledge of 12-factor App principles

The 12 - factor app principles are a set of guidelines for building software - as - a - service applications. They were developed by Heroku in 2011 to help developers create applications that are easy to deploy, scale, and maintain. Here is an overview of each principle:

Codebase: There is a single codebase tracked in a version control system, and it is used in multiple deploys. This ensures that all environments, from development to production, are based on the same codebase, reducing inconsistencies.
Dependencies: Explicitly declare and isolate dependencies. This means using tools like package managers to manage all the libraries and frameworks the app depends on, ensuring that the app runs in a consistent environment.
Config: Store configuration in the environment. This allows for easy customization of the app’s behavior based on the environment it’s running in, without changing the code. Configurations can include database connection strings, API keys, and other settings.
Backing Services: Treat backing services like databases and message queues as attached resources. The app should be able to connect to these services using a standard URL or connection string, making it easy to switch out one service for another.
Build, Release, Run: Strictly separate the build, release, and run stages. The build stage compiles the code and installs dependencies, the release stage combines the build with the configuration, and the run stage starts the app in the runtime environment.
Processes: Execute the app as one or more stateless processes. Each process should be independent and not rely on the state of other processes. This makes it easy to scale the app by adding more processes as needed.
Port Binding: Expose services via port binding. The app should listen on a specific port and make itself available to the outside world through that port. This allows the app to be easily deployed to different environments and integrated with other services.
Concurrency: Scale out via the process model. Instead of trying to make a single process handle more and more requests, add more processes to handle the load. This can be done horizontally by adding more instances of the app or vertically by adding more resources to a single instance.
Disposability: Maximize robustness with fast startup and graceful shutdown. The app should be able to start up quickly and be able to handle sudden shutdowns gracefully, saving any necessary data and cleaning up resources.
Dev/Prod Parity: Keep development, staging, and production environments as similar as possible. This helps to avoid issues that can arise when an app works fine in development but breaks in production due to differences in the environment.
Logs: Treat logs as event streams. Collect and analyze logs from all processes and services to gain insights into the app’s behavior and diagnose issues. Logs can include information about errors, user actions, and system events.
Admin Processes: Run admin/management tasks as one - off processes. These tasks can include database migrations, seed data insertion, and other administrative functions. They should be run separately from the regular app processes and follow the same principles as the app itself.

Relevance to Java & Spring Applications:

• Spring Boot naturally follows many 12-factor principles, like externalized config (Spring Cloud Config, Environment Variables) and embedded servers (Tomcat, Jetty).
• Docker & Kubernetes enable scalability (Factor 8 - Concurrency) and statelessness (Factor 6 - Processes).
• Log Aggregation can be done via ELK Stack, Prometheus, Grafana.

BQ for Job Interviews

Self - Introduction

Work/Project Summary

questions about your resume

Netflix

Adobe

Robinhood

TOP 15 behavioral questions

1. Why did you leave your last job?

2. Describe a major conflict within or outside your team and how you handled it, or how you dealt with a difficult team member.

3. Describe a time when you had difficulty completing a task or making progress.

4. If your manager asks you to change something that you think is already good enough, how would you handle it?

5. Why do you want to join our team?

6. Are you familiar with Agile `/ ˈædʒ(ə)l /` processes and Waterfall methodology `/ ˌmeθəˈdɑːlədʒi /`?

7. What does a typical day look like for you?

8. What do you think are the most important factors for a successful team ?

9. If you are working on a sprint and your manager suddenly assigns you a new task that needs to be finished as soon as possible, what would you do?

10. Tell me something about yourself that is not on your resume.

11. Tell me about a difficult project or challenge you faced and how you handled it.

13. Do you have on-call experience, and are you comfortable with overnight on-call duties?

14. Do you know what pair programming is, and what are your thoughts on it?

15. If you are mentoring a junior colleague and they propose a new idea to the team, how would you handle it?

16. Describe your code review process. What do you focus on during a code review?

fulltime job BQs

Pilot Training Questions

How to Answer a Corp-to-Corp Vendor’s Call?

Leetcode

Rest API

Knowledge of 12-factor App principles

Self - Introduction

Work/Project Summary

questions about your resume

Netflix

Adobe

Robinhood

TOP 15 behavioral questions

1. Why did you leave your last job?

2. Describe a major conflict within or outside your team and how you handled it, or how you dealt with a difficult team member.

3. Describe a time when you had difficulty completing a task or making progress.

4. If your manager asks you to change something that you think is already good enough, how would you handle it?

5. Why do you want to join our team?

6. Are you familiar with Agile / ˈædʒ(ə)l / processes and Waterfall methodology / ˌmeθəˈdɑːlədʒi /?

7. What does a typical day look like for you?

8. What do you think are the most important factors for a successful team ?

9. If you are working on a sprint and your manager suddenly assigns you a new task that needs to be finished as soon as possible, what would you do?

10. Tell me something about yourself that is not on your resume.

11. Tell me about a difficult project or challenge you faced and how you handled it.

12. Share a time when you made a mistake in a team setting, how you resolved it, and what you learned from the experience.

13. Do you have on-call experience, and are you comfortable with overnight on-call duties?

14. Do you know what pair programming is, and what are your thoughts on it?

15. If you are mentoring a junior colleague and they propose a new idea to the team, how would you handle it?

16. Describe your code review process. What do you focus on during a code review?

fulltime job BQs

Pilot Training Questions

How to Answer a Corp-to-Corp Vendor’s Call?

Leetcode

Rest API

Knowledge of 12-factor App principles

6. Are you familiar with Agile `/ ˈædʒ(ə)l /` processes and Waterfall methodology `/ ˌmeθəˈdɑːlədʒi /`?