Question

How should I use List<Data> dat = new List<Data>(); to temporary store data in my software? "Data" is a class in my code with variables(mainly Strings). When I try that method it doesn’t store data.

Answer 1

List is an interface, so you can’t instantiate it (call new List()) as it does not have a concrete implementation. To keep it simple, use one of the existing implementations, for example:

List<Data> dat = new ArrayList<Data>();

You can then use it like this:

Data data = new Data();
//initialise data here
dat.add(data);

You would probably benefit from reading the Java Tutorial on Collections.