Understanding the Use of Round Brackets in Java's Try-with-Resources Statement

What is the purpose of using parentheses () in the try-with-resources statement in Java?

try (
    ByteArrayOutputStream byteArrayStreamResponse = new ByteArrayOutputStream();
    HSLFSlideShow pptSlideShow = new HSLFSlideShow(
        new HSLFSlideShowImpl(
            Thread.currentThread().getContextClassLoader()
                .getResourceAsStream(Constants.PPT_TEMPLATE_FILE_NAME)
        )
    );
) {
    // code execution block,
} catch (Exception ex) {
    // handle the exception,
} finally {
    // close resources if necessary,
}

The parentheses used in the try statement denote the try-with-resources feature introduced in Java 7. This feature simplifies resource management by automatically closing resources when they are no longer needed, thereby preventing resource leaks.

try (BufferedReader reader = new BufferedReader(new FileReader("file.txt"))) {
    String line = reader.readLine();
    // Process the line
} catch (IOException e) {
    // Handle IOException
} // No need for finally block to close the reader

Causes

• To automatically manage resources such as file streams or database connections.
• To improve code readability and reduce boilerplate code related to resource management.

Solutions

• Use try-with-resources to declare and initialize resources within parentheses.
• Ensure that any resource declared implements the AutoCloseable interface.

Mistake: Not using resources that implement AutoCloseable.

Solution: Ensure all resources declared within the parentheses implement the AutoCloseable interface.

Mistake: Forgetting to handle exceptions appropriately within the try block.

Solution: Add catch blocks to handle specific exceptions.