exception - Closing a Java FileInputStream

Question

Alright, I have been doing the following (variable names have been changed):

FileInputStream fis = null;
try
{
    fis = new FileInputStream(file);

    ... process ...

}
catch (IOException e)
{
    ... handle error ...
}
finally
{
    if (fis != null)
        fis.close();
}

Recently, I started using FindBugs, which suggests that I am not properly closing streams. I decide to see if there's anything that can be done with a finally{} block, and then I see, oh yeah, close() can throw IOException. What are people supposed to do here? The Java libraries throw too many checked exceptions.

Answer 1

For Java 7 and above try-with-resources should be used:

try (InputStream in = new FileInputStream(file)) {
  // TODO: work
} catch (IOException e) {
  // TODO: handle error
}

If you're stuck on Java 6 or below...

This pattern avoids mucking around with null:

    try {
        InputStream in = new FileInputStream(file);
        try {
            // TODO: work
        } finally {
            in.close();
        }
    } catch (IOException e) {
        // TODO: error handling
    }

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For a more detail on how to effectively deal with close, read this blog post: Java: how not to make a mess of stream handling. It has more sample code, more depth and covers the pitfalls of wrapping close in a catch block.