Type Variables Increase Safety

• Type variables make generic code safer and easier to read
  • Impossible to add a String into an ArrayList<BankAccount>
  • Can add a String into a LinkedList intended to hold bank accounts

    ArrayList<BankAccount> accounts1 = new ArrayList<BankAccount>();
    LinkedList accounts2 = new LinkedList(); // Should hold BankAccount objects
    accounts1.add("my savings"); // Compile-time error
    accounts2.add("my savings"); // Not detected at compile time
    . . .
    BankAccount account = (BankAccount) accounts2.getFirst(); // Run-time error