Parent Child classes

Question

Hi All,
I have a really general question that I have not been able to solve.
Here is my sample code:
class parent {
public List mylist
public parent(){
child c = new child(this, mylist);
class child
private parent p;
private List mylist;
private String currentLine ="";
public child(parent p, List mylist){
this.p=p;
this.mylist = mylist;
BufferedReader in new BufferedReader(new FileReader("test.txt"));
while ((currentLine = in.readLine()) != null){
mylist.add(currentLine);
How do I return mylist in the child class back to the parent class? Or secondly, can I declare a List in the child class and have some way of passing it back to the parent class? I am not very familiar with the parent/child classes. If you can assist, I'd appreciate it. Thanks.

Answer 1

Actually....the main problem that I have is that I am using multi threading. Right now the problem that I have is that I can't write to the same output file with multiple children threads...not sure why.
class parent {
PrintWriter out;
public parent () {
out = new PrintWriter(new BufferedWriter(new FileWriter("output.txt")));
for (int i=0; i<10; i++){
childthread ct = new childthread(this);
public synchronized void Output (String output){
out.write(output);
}//end class parent
class child extends Thread{
parent p;
public child (parent p) {
this.p = p;
public void run(){
String thisLine = "test";
p.Output(thisLine);
}//end class child
How can I get all of my 10 threads to write to the same file. Since my parent thread is the one with the output file, each time the child thread calls the p.Output and passes the String..it should printout test in my output file...but it does not. Is there any reason why?
My output file should display "test" ten times. Please let me know what I am doing wrong...or how I can go about writing multiple threads to the same output file. Thank you.