# Io / Github / Biezhi / Java11 / Processor

## Overview
This module is a very small Java 11 Process API example. It appears to exist as a focused demonstration of how to inspect the currently running JVM process and print its process identifier (PID) using `ProcessHandle`. The package contains one executable example class, so the module is more of a learning/demo entry point than a layered subsystem.

The implementation is intentionally minimal: `main` acquires the current process handle and writes its PID to standard output. For a new engineer, the key thing to understand is that this module showcases the Java 9+ process API surface rather than introducing application-specific business logic.

## Key Classes and Interfaces

### `Example`
Source: [src/main/java/io/github/biezhi/java11/processor/Example.java](src/main/java/io/github/biezhi/java11/processor/Example.java)

This is the only class in the package and the package's only runtime entry point. It demonstrates the most basic use of `ProcessHandle` by asking the JVM for the current process and printing its PID.

#### Purpose
- Serve as a runnable example of the Java Process API.
- Show how to identify the running JVM process from inside the application.
- Provide a simple template for extending process inspection code later.

#### Method: `main(String[] args)`
Source: [Example.main(String[] args)](src/main/java/io/github/biezhi/java11/processor/Example.java:19)

- **What it does:**
  - Calls `ProcessHandle.current()` to obtain a handle for the current process.
  - Reads the process ID via `pid()`.
  - Prints the PID to standard output in Chinese text: `当前进程的 PID = ...`.
- **Parameters:**
  - `String[] args` is present because this is a standard Java entry point, but it is not used.
- **Returns:**
  - `void`.
- **Side effects:**
  - Writes a single line to stdout.
- **Why it matters:**
  - It demonstrates the simplest possible interaction with the process API and confirms that the running program can introspect its own process identity.

## How It Works

The execution flow is straightforward:

1. The JVM invokes `Example.main(String[] args)`.
2. The code asks the runtime for the current process using `ProcessHandle.current()`.
3. The process handle is queried for its PID.
4. The PID is printed to the console.

In Mermaid form, the flow looks like this:

```mermaid
flowchart TD
ExampleClass["io.github.biezhi.java11.processor.Example"] --> ProcessHandleCurrent["ProcessHandle.current()"]
ProcessHandleCurrent --> PrintPid["Print current process PID"]
```

This module does not contain branching logic, state management, or external integration. It is essentially a one-step demonstration of a JDK feature.

## Data Model

There are no domain entities, DTOs, or custom model classes in this package. The only notable runtime object is the JDK-provided `ProcessHandle`, which represents the current operating-system process.

## Dependencies and Integration

This package depends only on the Java runtime APIs shown in the source code:

- `java.lang.ProcessHandle`
- `java.lang.ProcessHandle.current()`
- `ProcessHandle.pid()`

No project-local dependencies, frameworks, or package-to-package relationships were resolved for this module.

## Notes for Developers

- `args` is unused, so this class is not designed around command-line input.
- The example prints directly to standard output rather than using logging.
- If you expand this module, the natural next step would be to inspect more of `ProcessHandle`'s capabilities, such as parent/child relationships or process metadata via `ProcessHandle.Info`.
- Because the module is a demo, it should be treated as illustrative code rather than a reusable service component.

## References

- [src/main/java/io/github/biezhi/java11/processor/Example.java](src/main/java/io/github/biezhi/java11/processor/Example.java)