Question

Is there is any feasible solution to have private constructor in abstract class..please advise

public abstract class BaseClass
{
    private String member;

    private BaseClass(String member)
    {
        this.member = member;
    }

    ... abstract methods...
}

Answer 1

abstract class can have a private constructor. But that class cannot be extended by another class. Instead of adding a static inner class inside the abstract class and extends that abstract class.

 abstract class  Base{
public abstract void set();

private Base(){
System.out.println("Private Constructor!");
}
static class Derived extends Base{
public void set(){
System.out.println("set() method implemented!");
}
}
public static void main(String[] args){
new Base.Derived().set();
}
}