loging

private String getDetailMessages(Throwable throwable){
    StringBuffer buffer = new StringBuffer();
    buffer.append(throwable.getMessage()).append("\n");
    StackTraceElement[] stackTrace = throwable.getStackTrace();
    for(StackTraceElement element : stackTrace) {
        if(element.getFileName().endsWith(".java")){
            buffer.append("\tat ").append(element.toString()).append("\n");
        }
    }
    return buffer.toString();
}