jodd-core/src/main/java/jodd/io/FileUtil.java
private static void checkDirCopy(final File srcDir, final File destDir) throws IOException {
		checkExists(srcDir);
		checkIsDirectory(srcDir);
		if (equals(srcDir, destDir)) {
			throw new IOException("Source '" + srcDir + "' and destination '" + destDir + "' are equal");
		}
	}
private static void checkDirCopy(final File srcDir, final File destDir) throws IOException {
		checkExists(srcDir);
		checkIsDirectory(srcDir);
		if (equals(srcDir, destDir)) {
			throw new IOException("Source '" + srcDir + "' and destination '" + destDir + "' are equal");
		}
	}
Checks that srcDir exists, that it is a directory and if srcDir and destDir are not equal.

@param srcDir  Source directory
@param destDir Destination directory
@throws IOException if any of the above conditions are not true.