[英]Why can't I create object outside any method
在編寫程序時,我遇到了一個方法外實例化的stackoverflow錯誤,因此我在Internet上搜索了該代碼,但我不了解任何合適的解決方案。
所以任何人都可以讓我擺脫混亂。 我正在使用聚合,因為它具有Has-a關系。下面是我的Mainpage.class,它將首先執行。
import java.util.Scanner;
public class Mainpage {
Scanner in = new Scanner(System.in);
People people;
public void openapp()
{
people = new People();
System.out.println("Welcome to the Chat");
System.out.println();
System.out.println("1. Newsfeed");
System.out.println("2. Chat");
System.out.println("3. Friends");
System.out.println("Enter your choice");
int input = in.nextInt();
switch(input)
{
case 1:
System.out.println("Newsfeed");
break;
case 2:
System.out.println("Chat");
break;
case 3:
System.out.println("Friends");
break;
default :
System.out.println("Invalid Input");
}
if(input == 3)
{
people.friends();
}
}
public static void main(String args[]){
Mainpage m = new Mainpage();
m.openapp();
}
}
下面是我的People.class代碼,將從Mainpage類的輸入中選擇朋友時調用
import java.util.Scanner;
public class People{
People ps = new People();
Scanner input = new Scanner(System.in);
public void friends()
{
System.out.println("Your friends are");
System.out.println();
System.out.println("Amit");
System.out.println("Rahul");
System.out.println("Ankita");
System.out.println("Enter the friend name to see info");
String fr = input.nextLine();
//ps.friend(fr);
switch(fr){
case "Amit":
System.out.println("Name: Amit");
System.out.println("DOB: 09-02-1993");
System.out.println("Age = 23");
System.out.println("Sex: M");
break;
case "Rahul":
System.out.println("Name: Rahul");
System.out.println("DOB: 11-10-1993");
System.out.println("Age = 23");
System.out.println("Sex: M");
break;
case "Ankita":
System.out.println("Name: Ankita");
System.out.println("DOB: 12-03-1993");
System.out.println("Age = 22");
System.out.println("Sex: M");
break;
default:
System.out.println("You have no one With name "+fr+" in your contact list");
System.out.println("Please again select the friends form the lists");
ps.friends();
}
}
我收到Stackoverflow錯誤,因此請清除我的疑問。
Exception in thread "main" java.lang.StackOverflowError
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
at People.<init>(People.java:4)
刪除People ps = new People();
從您的People
類中獲取,因為它將導致對People
的構造函數的無限調用。
調用new People()
將初始化實例變量,因此它將永遠遞歸調用People()
。
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