JDOM: cannot find symbol getAttribute()

Question

I want to get a list of the names of keys stored in a keystore.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>
<keystore>
<key name="key-01">
    <Verwendungszweck></Verwendungszweck>
    <Generation></Generation>
    <Version></Version>
    <Algorithmus></Algorithmus>
    <Keylength></Keylength>
    <Blocklength></Blocklength>
</key>

<key name="key-02">
    <Verwendungszweck></Verwendungszweck>
    <Generation></Generation>
    <Version></Version>
    <Algorithmus></Algorithmus>
    <Keylength></Keylength>
    <Blocklength></Blocklength>
</key>
</keystore>

Unfortunately Netbeans says that it "cannot find symbol keyNameAttribute = keyList.get(i).getAttribute("name");". I don't get why it's not working. Do you have any idea? This is my code:

    public List getKeyNames(){
    try {
        SAXBuilder builder = new SAXBuilder();
        Document document = builder.build(f);

        List keyNameList = new ArrayList();
        List keyList = new ArrayList();

        Element keystore = document.getRootElement();
        keyList = keystore.getChildren("key");
        for(int i=0; i<=keyList.size(); i++) {
            keyNameList.add((keyList.get(i)).getAttribute("name").getValue());
        }
        return keyNameList;
    } 
    catch (JDOMException e) {
        e.printStackTrace();
    }         
    catch(IOException e){
        e.printStackTrace();
        System.out.println(e.getMessage());
    } 
    return null;
}

your title, description and code show three different errors — wero, Feb 05 '16 at 08:30
I do see one error. Netbeans highlights getAttribute("name") ... — Jans, Feb 05 '16 at 08:37

score 3 · Accepted Answer · answered Feb 05 '16 at 08:35

Basically, you need to use generics. You're currently using raw types - so keyList.get(i) is an expression of type Object. It would also be cleaner to use an enhanced for loop (or Java 8 streams) - currently your for loop has an inappropriate upper bound anyway.

I suspect you want (pre-Java 8):

List<String> keyNameList = new ArrayList();
Element keystore = document.getRootElement();
for (Element element : keystore.getChildren("key")) {
    keyNameList.add(element.getAttribute("name").getValue());
}

(You should declare your method to return a List<String> too.)

If you're not familiar with generics already, I would strongly recommend that you read up on them immediately. They're a very important part of modern Java programming.

JDOM: cannot find symbol getAttribute()

1 Answers1