Abstract class constructor

Package java.io ClassDescriptionInputStreamThis abstract class is the superclass of all classes representing an input stream of bytes.InputStreamReaderAn InputStreamReader is a bridge from byte streams to character streams: It reads bytes and decodes them into characters using a specified charset .Package java.io – Oracle Help Center docs.oracle.com › javase › docs › api › java › package-summary

A Java abstract class is a class which cannot be instantiated, meaning you cannot create new instances of an abstract class. The purpose of an abstract class is to function as a base for subclasses .9 Mar 2015

An abstract class is a class that is declared abstract —it may or may not include abstract methods. Abstract classes cannot be instantiated, but they can be subclassed.