Get started with this introduction to using generics with the Java Collections ... we are declaring our generic variable as “E,” and this variable can be replaced by any object type we want.

Generics can be invariant, covariant, or contravariant, affecting how different types relate under inheritance. import java.util.List; import java.util.ArrayList; public class InvarianceExample ...

The most basic Java collection - the Array and a more enhanced collection - the ArrayList. We've encountered arrays ... Hand out start point We need to declare the type of things that go into the ...

When using ArrayList methods (like add()), the reference parameters and return type of a method must match the declared element type of the ArrayList. For example, we cannot add an Integer type value ...

As you can see in the following var examples, the left-hand side of the assignment does not reference a Java types such as long, double or ArrayList. Instead, it uses the Java var keyword, which ...