t****r
发帖数: 25 | 1 Parent.java:
public class Parent {
public Parent() {
System.out.println("parent");
}
}
Child.java:
public class Child extends Parent {
public Child() {
System.out.println("child");
}
public static void main(String[] args) {
Child c = new Child();
}
}
java Child, outputs:
parent
child
WHY?? |
g*s
发帖数: 2277 | 2 If you don't call super(xxx) or this(xxx) as the first line of code in a
constructor, Java will automatically insert a call to the default no-
argument superclass constructor super() for you.
【在 t****r 的大作中提到】
: Parent.java:
: public class Parent {
: public Parent() {
: System.out.println("parent");
: }
: }
: Child.java:
: public class Child extends Parent {
: public Child() {
: System.out.println("child");
|
g*s
发帖数: 2277 | 3 If you don't call super(xxx) or this(xxx) as the first line of code in a
constructor, Java will automatically insert a call to the default no-
argument superclass constructor super() for you.
【在 t****r 的大作中提到】
: Parent.java:
: public class Parent {
: public Parent() {
: System.out.println("parent");
: }
: }
: Child.java:
: public class Child extends Parent {
: public Child() {
: System.out.println("child");
|
B******N
发帖数: 445 | 4 you can use a debugger to step through, which will help you to understand
the instantiation sequence of every bit, and that will help you to
understand more OO.
【在 t****r 的大作中提到】
: Parent.java:
: public class Parent {
: public Parent() {
: System.out.println("parent");
: }
: }
: Child.java:
: public class Child extends Parent {
: public Child() {
: System.out.println("child");
|
