Iterating over the content of a text file line by line – is there a best practice? (vs. PMD’s AssignmentInOperand)

I know is an old post but I just had the same need (almost) and I solve it using a LineIterator from FileUtils in Apache Commons.
From their javadoc:

LineIterator it = FileUtils.lineIterator(file, "UTF-8");
try {
    while (it.hasNext()) {
    String line = it.nextLine();
    // do something with line
    }
} finally {
    it.close();
}

Check the documentation:
http://commons.apache.org/proper/commons-io/javadocs/api-release/org/apache/commons/io/LineIterator.html