Behavior of polymorphic methods inside constructors
class Glyph {
void draw() {
System.out.println("Glyph.draw()");
}
Glyph() {
System.out.println("Glyph() before draw()");
draw();
System.out.println("Glyph() after draw()");
}
}
class RoundGlyph extends Glyph {
private int radius = 1;
RoundGlyph(int r) {
radius = r;
System.out.println("RoundGlyph.RoundGlyph(), radius = " + radius);
}
void draw() {
System.out.println("RoundGlyph.draw(), radius = " + radius);
}
public static void main(String[] args) {
new RoundGlyph(5);
}
}
Output:
Glyph() before draw()
RoundGlyph.draw(), radius = 0
Glyph() after draw()
RoundGlyph.RoundGlyph(), radius = 5
在构造器中调用多态方法,虽然对象没有完全构造好,但是多态也会发生!!