Abstract is keyword which is used in java programming language to achieved the Abstraction which is more powerful concept in java programming language. If we wants to create the Abstract class then declare the class with Abstract keyword. It can be applied to a class and methods. An abstract class cannot be directly instantiated. It must be placed before the variable type or the method return type. It is recommended to place it after the access modifier and after the static keyword. A non-abstract class is a concrete class. An Abstract class cannot be final. Abstract classes may or may not contain abstract methods which have no body. But if a class have at least one abstract method, then the class must be declared abstract. To use an Abstract class you have to inherit it from another class, provide implementations to the abstract methods in it.