java-based interview questions: ORDINARY classes and abstract classes What are the differences there?

Key: abstract modifier (abstract method), a specific implementation process, instances of subclasses of the parent class implementation of the abstract

1. Abstract class can not contain ordinary method, it can be instantiated;
2. Abstract class, abstract class, all methods are automatically considered to be abstract methods, no implementation process, can not be instantiated; subclass of the abstract class is an abstract class unless otherwise must implement the abstract class declaration method