V6128. Using a Closeable object after it was closed can lead to an exception.

The analyzer has detected a method call on an object that had already been closed using the closemethod. This may result in an exception being thrown.

The example:

public void appendFileInformation(String path) throws IOException {
    FileInputStream is = new FileInputStream(path);
    // ....
    is.close();
    // ....
    if (is.available() == 0) {
        System.out.println("EOF");
    }
    // ....
}

The condition ensures that the file has been completely read. The check compares the number of remaining bytes to zero. However, since the close method is called on the is variable before, calling the available method results in an IOException with the message Stream Closed. That is because the resources held by is are already released.

Look at a proper implementation of appendFileInformation:

public void appendFileInformation(String path) throws IOException {
    try (FileInputStream is = new FileInputStream("out.txt")) {
        // ....
        if (is.available() == 0) {
            System.out.println("EOF");
        }
        // ....
    }
}

To ensure the method works correctly, consider using try-with-resources. In this case:

• the resources held by the is object will be automatically released after the try block ends;
• the object cannot be accessed outside the try block, which adds an extra layer of protection against IOException.
• resources are properly released even if an exception occurs inside the try block.

This diagnostic is classified as:

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