# Page Not Found

The URL `study/backend/java-8-in-action/2020-03-10-java8inaction-chap10` does not exist. This page may have been moved, renamed, or deleted.

## Suggested Pages

You may be looking for one of the following:
- [10장 null 대신 Optional](https://incheol-jung.gitbook.io/docs/study/java-8-in-action/2020-03-10-java8inaction-chap10.md)
- [11장 CompletableFuture: 조합할 수 있는 비동기 프로그래밍](https://incheol-jung.gitbook.io/docs/study/java-8-in-action/2020-03-10-java8inaction-chap11.md)
- [12장 새로운 날짜와 시간 API](https://incheol-jung.gitbook.io/docs/study/java-8-in-action/2020-03-10-java8inaction-chap12.md)
- [13장 함수형 관점으로 생각하기](https://incheol-jung.gitbook.io/docs/study/java-8-in-action/2020-03-10-java8inaction-chap13.md)
- [14장 함수형 프로그래밍 기법](https://incheol-jung.gitbook.io/docs/study/java-8-in-action/2020-03-10-java8inaction-chap14.md)

## How to find the correct page

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### Option 1 — Ask a question (recommended)

Perform an HTTP GET request on the following URL with the `ask` and `goal` query parameters:

```
GET https://incheol-jung.gitbook.io/docs/study/java-8-in-action/2020-03-10-java8inaction-chap10.md?ask=<question>&goal=<user_goal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is what the user is ultimately trying to achieve, the reason they need the answer. Sharing it helps GitBook give you a better, more relevant answer. A goal is most helpful when it describes the outcome the user wants rather than restating the question. For example, with `ask=how do I create an API token`, a goal like `automate deployments from our CI pipeline` lets GitBook tailor the answer to that use case.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

### Option 2 — Browse the documentation index

Full index: https://incheol-jung.gitbook.io/docs/sitemap.md

Use this to discover valid page paths or navigate the documentation structure.

### Option 3 — Retrieve the full documentation corpus

Full export: https://incheol-jung.gitbook.io/docs/llms-full.txt

Use this to access all content at once and perform your own parsing or retrieval. It will be more expensive.

## Tips for requesting documentation

Prefer `.md` URLs for structured content, append `.md` to URLs (e.g., `/docs/study/java-8-in-action/2020-03-10-java8inaction-chap10.md`).

You may also use `Accept: text/markdown` header for content negotiation.