Returns the URI formed by appending a period (".") followed by the specified file extension to the last path segment of this URI, if it is hierarchical with a non-empty path ending in a non-empty segment; otherwise, this URI is returned unchanged.
The extension is appended regardless of whether the segment already contains an extension.
@exception java.lang.IllegalArgumentException iffileExtension is not a valid segment (portion) according to {@link #validSegment}.
All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.