# Io / Github / Biezhi / Java11 / Singlefile

## Overview

This module appears to be a minimal Java 11 single-file execution example. It exists to demonstrate that a `.java` source file can be run directly without a separate manual compile step, which is the core idea behind JEP 330. The module currently contains one class, `HelloWorld`, whose only job is to print a greeting to standard output.

## Key Classes and Interfaces

### `HelloWorld`
Source: [java11-examples-master/src/main/java/io/github/biezhi/java11/singlefile/HelloWorld.java](java11-examples-master/src/main/java/io/github/biezhi/java11/singlefile/HelloWorld.java)

`HelloWorld` is the entire module. It is a simple entry-point class designed to demonstrate Java 11's single-file source execution workflow rather than provide reusable application logic.

#### Purpose
The class shows how a developer can place runnable code directly in a source file and execute it with `java HelloWorld.java`. The file-level comment explains that this is effectively equivalent to compiling to memory and then running the generated class, but the developer does not need to perform those steps manually.

#### Key method
- `main(String[] args)` — [HelloWorld.main(String[] args)](java11-examples-master/src/main/java/io/github/biezhi/java11/singlefile/HelloWorld.java:19)
  - **What it does:** prints `Hello Guys, this is Java 11.` to standard output.
  - **Parameters:** accepts the standard `String[] args` entry-point parameter, but does not use it.
  - **Returns:** `void`.
  - **Side effects:** writes one line to the console via `System.out.println(...)`.

## How It Works

The execution flow is intentionally straightforward:

1. The Java runtime loads the `HelloWorld` source file.
2. The `main` method is invoked as the program entry point.
3. The method sends a fixed greeting string to standard output.

This module does not branch, transform data, or depend on any other local classes. Its value is instructional: it demonstrates the mechanics of single-file execution with the smallest possible example.

## Mermaid Relationship Diagram

```mermaid
flowchart LR
HelloWorld["HelloWorld"] --> Main["main(String[] args)"]
Main --> Output["Prints Hello Guys, this is Java 11."]
```

## Dependencies and Integration

There are no package dependencies resolved for this module, and the source file does not import any external libraries. The only integration point is the Java runtime itself, which provides the `main` entry point contract and standard output stream.

The file comment references [JEP 330](http://openjdk.java.net/jeps/330), which is the Java Enhancement Proposal that introduced source-file launching. That reference explains why this example exists: it is meant to show the direct execution workflow supported by Java 11.

## Notes for Developers

- This module is intentionally minimal. If you extend it, you will likely want to keep the `main` method as the runnable entry point and add new behavior behind additional helper methods or classes.
- The `args` parameter is currently unused. If you need command-line configuration, that is the natural place to start.
- Because this is a single-file example, there is no package-level orchestration or shared domain model to maintain.
- The class comment is in Chinese and documents the same execution idea as the code itself: `java HelloWorld.java` is the intended invocation pattern.

## Data Model

There is no domain data model in this module. The only data manipulated is the fixed string literal passed to `System.out.println(...)`.