9.22

原因是没有初始构造

 

 

package org.example;

public class InitializeBlockClass {

public int field=100;
{
field=200;
}
public InitializeBlockClass(int field) {
this.field = field;
}

public InitializeBlockClass() {
}

public static void main(String[] args) {
InitializeBlockClass obj=new InitializeBlockClass();
System.out.println(obj.field);
obj=new InitializeBlockClass(300);
System.out.println(obj.field);
}
}

 

 

 

package org.example;

public class InitializeBlockClass {
{
field=200;
}
public int field=100;

public InitializeBlockClass(int field) {
this.field = field;
}

public InitializeBlockClass() {
}

public static void main(String[] args) {
InitializeBlockClass obj=new InitializeBlockClass();
System.out.println(obj.field);
obj=new InitializeBlockClass(300);
System.out.println(obj.field);
}

}