下面通过例子来说明:
父类
public class father {
static{//静态块
System.out.println("father'sSTATIC free block running");
}
{//非静态块
System.out.println("father'sfree block running");
}
public father(){
System.out.println("father'sconstructor running");
}
}
子类
{//非静态块
System.out.println("son's freeblock running");
}
public son() {
// TODO Auto-generated constructor stub
System.out.println("son'sconstructor running");
}
}
主函数所在类
public class test{
public static void main(String[] args) {
Class f;
try {
System.out.println("--------beforeload father--------");
f=Class.forName("freeblock.father");
System.out.println("--------afterload father---------");
System.out.println("--------beforeinitial father object--------");
f.newInstance();
System.out.println("--------afterinitial father object--------");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
Class s;
try {
System.out.println("-------beforeload son--------");
s=Class.forName("freeblock.son");
System.out.println("--------afterload son-------");
System.out.println("--------beforeinitial son object----------");
s.newInstance();
System.out.println("--------afterinitial son object-----------");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
}
}
执行结果:
--------before loadfather--------
father's STATIC free blockrunning
--------after loadfather---------
--------before initial fatherobject--------
father's free block running
father's constructor running
--------after initial fatherobject--------
-------before load son--------
son's STATIC free block running
--------after load son-------
--------before initial sonobject----------
father's free block running
father's constructor running
son's free block running
son's constructor running
--------after initial son object-----------