Question: I want to write an `ArrayList<String>` into a text file. 

The `ArrayList` is created with the code:

```
ArrayList arr = new ArrayList();

StringTokenizer st = new StringTokenizer(
    line, ":Mode set - Out of Service In Service");

while(st.hasMoreTokens()){
    arr.add(st.nextToken());    
}

```

Answer: 
If you want to serialize the ArrayList object to a file so you can read it back in again later use ObjectOuputStream/ObjectInputStream writeObject()/readObject() since ArrayList implements [Serializable](http://download.oracle.com/javase/1.4.2/docs/api/java/io/Serializable.html). It's not clear to me from your question if you want to do this or just write each individual item. If so then Andrey's answer will do that.
I think you can also use BufferedWriter :

```
BufferedWriter writer = new BufferedWriter(new FileWriter(new File("note.txt")));

String stuffToWrite = info;

writer.write(stuffToWrite);

writer.close();

```

and before that remember too add

```
import java.io.BufferedWriter;

```