About abstract classes in java

I learned because I didn't understand java abstract.


-Cannot create an instance directly ยท Force subclasses to override -It is necessary to write a constructor in a subclass


abstract class Abst_sample {
    abstract void abstractMethod(int num, String str);
    void nonAbstractMethod() {
        System.out.println("Output from non-abstract method");
public class sample extends Abst_sample {
    public static void main(String[] args) {
        sample aaa = new sample();   
//After inheriting, it creates its own instance and calls abstractMethod.
        aaa.abstractMethod(3, "Test");
    public void abstractMethod(int num, String str) {
        System.out.println("Argument int num= " + num + " /Argument String str= "+ str);

I think it's an image that gives an instruction to "use such a method".

When developing with a large number of people, such a function will be needed.

There is no loss to remember.



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