# Io / Github / Biezhi / Java11 / Trywithresources

## Overview

This module appears to be a small JDK 11 example that demonstrates the try-with-resources syntax using a `BufferedReader` opened on `README.md`. Its purpose is to show how a resource can be declared outside the `try` header and still be automatically closed when the block finishes.

The module is intentionally minimal: one class, one entry point, and one concrete file-reading example. That makes it useful as a teaching or reference snippet for engineers who want to understand the resource-management pattern without extra framework or application code.

## Key Classes and Interfaces

### [Example](src/main/java/io/github/biezhi/java11/trywithresources/Example.java)

`Example` is the only class in the package and serves as the executable demonstration. It does not model domain data or expose reusable APIs; instead, it shows the mechanics of try-with-resources in the simplest possible form.

#### Purpose

The class opens `./README.md` with a `FileReader`, wraps it in a `BufferedReader`, and then reads the file line by line. The core lesson is that the `BufferedReader` is placed into the try-with-resources block as an already-created variable, which is a style supported in later Java versions.

#### Key method

- [Example.main(String[] args)](src/main/java/io/github/biezhi/java11/trywithresources/Example.java)
  - **Parameters:** `String[] args`, though the method does not inspect command-line arguments.
  - **Returns:** `void`.
  - **Throws:** `Exception`, so callers do not need fine-grained exception handling in this sample.
  - **Behavior:**
    - Creates a `BufferedReader` around a `FileReader` for `./README.md`.
    - Enters `try (reader1)` to register the existing reader as an auto-closeable resource.
    - Loops while `reader1.ready()` is true and prints each line with `System.out.println(reader1.readLine())`.
  - **Side effects:** Reads from the local filesystem and writes file contents to standard output.

## How It Works

The execution flow is straightforward:

1. `main` constructs a `FileReader` for `./README.md`.
2. That `FileReader` is wrapped in a `BufferedReader` named `reader1`.
3. The code enters `try (reader1)`, which registers the existing variable as a resource to be closed automatically.
4. Inside the block, the code checks `reader1.ready()` before each read.
5. Each available line is printed to standard output.
6. When the block exits, the reader is closed automatically, even though there is no explicit `close()` call.

The sample is intentionally focused on resource lifetime rather than error recovery, parsing, or transformation logic.

### Mermaid relationship diagram

```mermaid
flowchart TD
ExampleClass["Example"]
MainMethod["main(String[] args)"]
BufferedReaderNode["BufferedReader"]
FileReaderNode["FileReader"]
ReadmeFile["README.md"]
ExampleClass --> MainMethod
MainMethod --> BufferedReaderNode
MainMethod --> FileReaderNode
MainMethod --> ReadmeFile
```

## Dependencies and Integration

This module uses only standard JDK I/O types:

- `java.io.FileReader` to open the file.
- `java.io.BufferedReader` to read text efficiently.

There are no project-local dependencies, no framework integrations, and no cross-module links in the indexed source. The only external input is the `README.md` file in the repository root, and the only output is console text.

## Notes for Developers

- The code assumes `./README.md` exists relative to the process working directory. If it does not, `main` will fail while constructing the `FileReader`.
- `reader1.ready()` is used as the loop condition. In general Java I/O code, engineers should be careful with `ready()` because it does not always mean “more lines exist” in every reader implementation, but here it works as a compact demo.
- Because the method throws `Exception`, this sample prioritizes clarity over precise error handling.
- The example is best treated as documentation code rather than production code. If you extend it, consider using `Files.newBufferedReader(...)`, a `try` block that includes the resource declaration directly, and explicit exception handling or logging.