Java – should private instance variables be accessed in constructors through getter and setter methods?

I know that private instance variables are accessed through their public getter and setter methods

But when I generate a constructor with the help of the IDE, it initializes instance variables directly instead of initializing them through the setter method

Q1. So I should change the code of IDE generated constructors to initialize these instance variables through their setter methods

Q2. If so, why doesn't the IDE generate constructor code in this way?

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>I use eclipse and NetBeans IDE, which is a common problem But according to @ lords' question, the answer depends on whether our constructor is public or protected, private or private?

Solution

You should not call non - Final methods from constructors Class constructor is used to initialize an object, and the object is not in a consistent state until the constructor returns If your constructor calls a non final method that is later overridden by a subclass, you can get strange and unexpected results because the object is not fully initialized when the overridden method is called

Consider this example:

class A {
    private int x;

    public A() {
        setX(2);
    }

    public void setX(int x) {
        this.x = x;
    }

    public int getX() {
        return x;
    }
}

class B extends A {
    private int number = 10;

    @Override        
    public void setX(int x) {
        // set x to the value of number: 10
        super.setX(number);
    }
}

public class Test {
    public static void main(String[] args) {
        B b = new B();
        // b.getX() should be 10,right?
        System.out.println("B.getX() = " + b.getX());
    }
}

The output of the program is:

B.getX() = 0

The reason is that when setx is called, the number member of B is not initialized, so its default value of 0.0 is used

This article has a more thorough explanation of effective Java