title: Different types of lists
body: <p>Hello I am studying Java and I am just confused about a question that keeps coming up in my exams.</p>
  
  <p>We are told to use a class for our collections.</p>
  
  <p>Usually in my main class I just make an arraylist of the type I need like bank accounts or whatever. But I think we are supposed to make a class for all our data. I tried this and made them static and have the class abstract because I don't need to make copies of the class itself. </p>
  
  <p>What I want to know is why don't people just make a list type that can do everything an arraylist and list can do in one, why is there different types? What are the benifits of having different types? Ps does a collection just mean a class for all your data?</p>