Is abstract class necessary in Java?

It’s not necessary for an abstract class to have abstract method . We can mark a class as abstract even if it doesn’t declare any abstract methods. If abstract class doesn’t have any method implementation, its better to use interface because java doesn’t support multiple class inheritance.

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Which Java class is abstract class?

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

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