Help with some errors in my program

[kbud123]

I'm a new java student (currently in computer programming 101) I'm getting an error I've never seen before with this program...


import java.util.ArrayList;
public class Thirteen
{
public static void main (String[] args)
{
ArrayList nameList = new ArrayList();
nameList.add("James");
nameList.add("Catherine");
nameList.add("Bill");

for (int index = 0; index < nameList.size(); index++)
{
System.out.println("Index: " + index + "Name: " + nameList.get(index));
}
nameList.add(1, "Mary");

System.out.println("After the changes, " + "here are the items now:");

for (int index = 0; index < nameList.size(); index++)
{
System.out.println("Index: " + index + " Name: " + nameList.get(index));
}}}



I'm getting the error:

Note: Thirteen.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

can someone please explain this to me ... thank you

Sorry if this is in the wrong topic

[sunde887]

That's not an error, it's a warning. If you wanna read the details google "java generics tutorial", short story, when you declare the array list do it like this

ArrayList<String> varName = new ArrayList<String>();

Notice the added parameter in between <>, this specifies the type the array list will hold.

[kbud123]

thanks a bunch.. quick response too :) !

[sunde887]

You are welcome, glad to have helped. Please mark your thread solved with the thread tools at the top.

[kbud123]

one more thing if you dont mind...

ArrayList<String> varName = new ArrayList<String>();

what do i replace string with if i want to use an array of integers?

[sunde887]

You can't use primitives for the type, you can however; use the wrapper class which has similar names to the primitive type. int would be Integer, double is Double, etc. Lookup autoboxing for more details.