private File createTemporaryFile(String filename) throws HelloSignException {
        String prefix = filename.substring(0, filename.indexOf("."));
        String postfix = filename.substring(filename.indexOf(".") + 1, filename.length());
        if (prefix == null || postfix == null) {
            throw new HelloSignException("Invalid file name: " + prefix + "." + postfix);
        }
        File f = null;
        try {
            f = File.createTempFile(prefix, "." + postfix);
        } catch (Exception ex) {
            throw new HelloSignException(ex);
        }
        return f;
    }
private File createTemporaryFile ( String filename ) throws HelloSignException { String prefix = filename . substring ( 0 , filename . indexOf ( "." ) ) ; String postfix = filename . substring ( filename . indexOf ( "." ) + 1 , filename . length ( ) ) ; if ( prefix == null || postfix == null ) { throw new HelloSignException ( "Invalid file name: " + prefix + "." + postfix ) ; } File f = null ; try { f = File . createTempFile ( prefix , "." + postfix ) ; } catch ( Exception ex ) { throw new HelloSignException ( ex ) ; } return f ; }
Helper method to create a temporary file.

@param filename String
@return File temporary file handle
@throws HelloSignException thrown if the file cannot be created