Java 9 try-with-resources Improvement

Java

224

java9

12

try-with-resources

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loveprogramming viết ngày 19/04/2021

https://grokonez.com/java/java-9/java-9-try-resources-improvement

Java 9 try-with-resources Improvement

Java 7 introduces a new approach for closing resources by try-with-resources statement. After that, Java 9 try-with-resources makes an improved way of writing code. Now we can simplify our code and keep it cleaner and clearer.

Related post: Java 7 – try-with-resources Statement

1. Java 7 try-with-resources

This is the way we use it from Java 7:

try (BufferedReader br = new BufferedReader(new FileReader("C://readfile/input.txt"))) {
    String line;
    while (null != (line = br.readLine())) {
        // processing each line of file
        System.out.println(line);
    }
} catch (IOException e) {
    e.printStackTrace();
}

It is good, but we have to declare the variable in try() block.
That's because we can't use resource which is declared outside the try() block within it. If resource is already declared outside, we should re-refer it with local variable:

// BufferedReader is declared outside try() block
BufferedReader br = new BufferedReader(new FileReader("C://readfile/input.txt"));

try (BufferedReader inBr = br) {
        // ...
    }
} catch (IOException e) {
    // ...
}

2. Java 9 try-with-resources improvement

Java 9 make things simple:

https://grokonez.com/java/java-9/java-9-try-resources-improvement

Java 9 try-with-resources Improvement