---

# (DD10) Business Logic — Example.main() [6 LOC]

| Field | Value |
|-------|-------|
| Fully Qualified Name | `io.github.biezhi.java11.http.Example` |
| Layer | Utility |
| Module | `http` (Package: `io.github.biezhi.java11.http`) |

## 1. Role

### Example.main()

This method is the executable entry point for the Java 11 HTTP client sample application. Its business role is to launch one demonstration scenario from a set of documented HTTP use cases, allowing a developer or tester to run a specific network interaction without navigating the rest of the example methods. In the current implementation, it activates the asynchronous POST workflow, which constructs a JSON payload and submits it to a remote HTTP endpoint for demonstration purposes. The commented lines show that the same entry point can be switched to other sample flows, such as synchronous GET, asynchronous GET, or HTTP/2 request execution, but only one scenario is actually invoked at runtime. This is a dispatcher-style entry method rather than a domain service: it does not transform business entities or persist records, but orchestrates which sample operation should run. Its larger-system role is to serve as the runnable launchpad for the `http` package examples and to provide a convenient integration test harness for HTTP client behavior.

## 2. Processing Pattern (Detailed Business Logic)

```mermaid
flowchart TD
    START(["main(args)"])
    COMMENT_SYNC_GET(["Commented option - syncGet(\"https://biezhi.me\")"])
    COMMENT_ASYNC_GET(["Commented option - asyncGet(\"https://biezhi.me\")"])
    CALL_ASYNC_POST(["Call asyncPost()"])
    COMMENT_HTTP2(["Commented option - http2()"])
    END_NODE(["Return / Next"])

    START --> COMMENT_SYNC_GET
    COMMENT_SYNC_GET --> COMMENT_ASYNC_GET
    COMMENT_ASYNC_GET --> CALL_ASYNC_POST
    CALL_ASYNC_POST --> COMMENT_HTTP2
    COMMENT_HTTP2 --> END_NODE
```

The method contains no runtime branching because the alternative calls are commented out. The effective processing path is a single dispatch to `asyncPost()`, while the other sample flows remain available as manual switchable options in source control.

## 3. Parameter Analysis

| No | Parameter Name | Type | Business Description |
|----|---------------|------|---------------------|
| 1 | `args` | `String[]` | Command-line arguments for the sample application launcher. In this method they are not inspected, so they do not affect processing; the method always invokes the asynchronous POST example regardless of the provided values. |

External state read by the method at the end of execution:
- No instance fields are read.
- No external configuration or input values are consumed.
- The method depends only on the static `asyncPost()` routine in the same class.

## 4. CRUD Operations / Called Services

### Pre-computed evidence from code analysis graph:

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|----------------------|
| - | `Example.asyncPost` | Example | - | Calls `asyncPost` in `Example` |

Analyze all method calls within this method and classify each as a CRUD operation.

| CRUD | SC / CBS | SC Code | Entity / DB | Operation Description |
|------|----------|---------|-------------|---------------------|
| R | `asyncPost()` | Example | httpbin.org/post (remote HTTP endpoint) | Executes the asynchronous HTTP POST sample and waits for the remote response body and status code to be printed. |

## 5. Dependency Trace

Trace who calls this method and what this method ultimately calls.

| # | Caller (Screen/Batch) | Call Chain (Full Path to this Method) | Terminal (SC / CRUD / Entity) |
|---|----------------------|--------------------------------------|-------------------------------|
| 1 | Batch/Utility launcher | `Example.main` | `asyncPost() [R] httpbin.org/post` |

## 6. Per-Branch Detail Blocks

**Block 1** — [SEQUENTIAL] `(startup dispatch)` (L188-L193)

> Entry point for the sample application. It presents alternative HTTP demos in comments and executes the asynchronous POST demo.

| # | Type | Code |
|---|------|------|
| 1 | EXEC | `// syncGet("https://biezhi.me");` // commented alternative HTTP GET sample |
| 2 | EXEC | `// asyncGet("https://biezhi.me");` // commented alternative asynchronous HTTP GET sample |
| 3 | CALL | `asyncPost();` // runs the asynchronous HTTP POST demonstration |
| 4 | EXEC | `// http2();` // commented alternative HTTP/2 sample |

## 7. Glossary

| Term | Type | Business Meaning |
|------|------|------------------|
| `args` | Field / Parameter | Command-line arguments passed to the Java launcher. In this method they are ignored and do not alter execution. |
| async | Acronym | Asynchronous execution model — the caller does not block while the HTTP request is in flight. |
| GET | Acronym | HTTP retrieval method used to fetch a resource from a server. |
| POST | Acronym | HTTP submission method used to send data to a server. |
| HTTP | Acronym | Hypertext Transfer Protocol — the transport protocol used for web requests. |
| HTTP/2 | Acronym | Second major version of HTTP with multiplexing and protocol improvements. |
| JSON | Acronym | JavaScript Object Notation — structured text format used for the request body in the sample flow. |
| `httpbin.org/post` | External endpoint | Public demonstration endpoint that echoes posted HTTP request content for client testing. |
| `syncGet` | Method name | Synchronous GET sample method, kept as a commented alternative entry path. |
| `asyncGet` | Method name | Asynchronous GET sample method, kept as a commented alternative entry path. |
| `asyncPost` | Method name | Asynchronous POST sample method that is actually invoked by `main()`. |
| `http2` | Method name | HTTP/2 sample method, kept as a commented alternative entry path. |
| `Example` | Class | Sample application class that groups HTTP client demonstrations. |