What is Eraser in Java?

2. The simplest eraser is just a paintbrush that draws using the background color. ‘erasing’ the foreground.

What is bounded type parameter?

There may be times when you want to restrict the types that can be used as type arguments in a parameterized type. For example, a method that operates on numbers might only want to accept instances of Number or its subclasses. This is what bounded type parameters are for.

What is type erasure in Scala?

Type erasure refers to the runtime encoding of parameterized classes in Scala. It is simply performed by Scala compiler in which it removes all the generic type information after compilation. In Scala, generics are erased at runtime, which means that the runtime type of List[Int] and List[Boolean] is actually the same.

What is covariance and Contravariance in generics?

Covariance and contravariance are terms that refer to the ability to use a more derived type (more specific) or a less derived type (less specific) than originally specified. Generic type parameters support covariance and contravariance to provide greater flexibility in assigning and using generic types.

How do I restrict a generic type in Java?

Whenever you want to restrict the type parameter to subtypes of a particular class you can use the bounded type parameter. If you just specify a type (class) as bounded parameter, only sub types of that particular class are accepted by the current generic class.

What is bounds in Java?

Bounds objects define a convex, closed volume that is used for various intersection and culling operations. Constructor Summary. Bounds() Constructs a new Bounds object. Method Summary.

What are the disadvantages of generics in Java?

Disdvantages of Generics: Generic types can be derived from most base classes, such as MarshalByRefObject (and constraints can be used to require that generic type parameters derive from base classes like MarshalByRefObject). However, the .NET Framework does not support context-bound generic types.

How can I restrict Java generics?

Bounded types can be used to restrict the bounds of the generic type by specifying the extends or the super keyword in the type parameter section to restrict the type by using an upper bound or lower bound, respectively.

Why are generics erased in arrays in Java?

However, Java does not allow the array to be generic. The reason for this is that in Java, arrays contain information related to their components and this information is used to allocate memory at runtime. When generics are used, due to type erasure, the byte code does not contain any generics information.

What is generic method in Java?

Java Generic methods and generic classes enable programmers to specify, with a single method declaration, a set of related methods, or with a single class declaration, a set of related types, respectively. Generics also provide compile-time type safety that allows programmers to catch invalid types at compile time.