liquibase-core/src/main/java/liquibase/util/file/FilenameUtils.java
public static String removeExtension(String filename) {
        if (filename == null) {
            return null;
        }
        int index = indexOfExtension(filename);
        if (index == -1) {
            return filename;
        } else {
            return filename.substring(0, index);
        }
    }
public static String removeExtension(String filename) {
        if (filename == null) {
            return null;
        }
        int index = indexOfExtension(filename);
        if (index == -1) {
            return filename;
        } else {
            return filename.substring(0, index);
        }
    }
Removes the extension from a filename.
<p>
This method returns the textual part of the filename before the last dot.
There must be no directory separator after the dot.
<pre>
foo.txt    --> foo
a\b\c.jpg  --> a\b\c
a\b\c      --> a\b\c
a.b\c      --> a.b\c
</pre>
<p>
The output will be the same irrespective of the machine that the code is running on.

@param filename  the filename to query, null returns null
@return the filename minus the extension