ensure that FileInputStream is closed to avoid resource leakage

[hansenmc]

Changed test for instanceof File to instanceof FileInputStream, so that
FileInputStreams will be closed.

Currently, this condition always fails and FileInputStreams are not
being closed when they should.

[sammefford]

@hansenmc I can't merge this without a unit test. I'll keep it so I can add a unit test when I get time. If you beat me to it, I'll be able to merge this.

[hansenmc]

Actually, now that I take a closer look - the close() is unnecessary and that code block can be removed altogether. So, rather than a possible memory leak, it's unnecessary, closing the already closed FileInputStream.

If a File is passed in, then content is assigned as a new FileInputStream(), which then uses try-with-resources to read with an InputStreamReader, which will automatically invoke close().

So, whether a File or FileInputStream were sent in, they should always be read with the InputStreamReader and automatically closed.

I added a specific test to demonstrate that FileInputStream is indeed being closed automatically and removed that code block. I couldn't think of a way to demonstrate/test File, but if you look at that section of code, it should be apparent.

[sammefford]

Analysis looks perfect to me. merging. Thanks!