重新拋出異常時調用序列的差異

Question

考慮以下類與方法：a（）調用b（），然後調用c（）。

public class ReThrower { 

    public static void a(int a1){ 
     try{ 
      a1+=1; 
      b(a1); 
     } 
     catch(ArithmeticException e){ 
      System.out.println("Exception caught at a"); 
      throw e; 
     } 
    } 

    public static void b(int b1){ 
     try{ 
      b1+=1; 
      c(b1); 
     } 
     catch(ArithmeticException e){ 
      System.out.println("Exception caught at b"); 
      throw e; 
     } 

    } 

    public static void c(int c1){ 
     int zero=0,result; 
     try{ 
      result=c1/zero; 
     } 
     catch(ArithmeticException e){ 
      System.out.println("Exception caught at c"); 
      e.printStackTrace(); 
      throw e; 
     } 

    } 

    public static void main(String[] args) { 
     a(5); 
    } 

} 

當我跑上面的代碼中，初始輸出接收到的是：

Exception caught at c 
java.lang.ArithmeticException:/by zero 
Exception caught at b 
Exception caught at a 
    at com.atul.security.ReThrower.c(ReThrower.java:31) 
    at com.atul.security.ReThrower.b(ReThrower.java:20) 
    at com.atul.security.ReThrower.a(ReThrower.java:10) 
    at com.atul.security.ReThrower.main(ReThrower.java:46) 
Exception in thread "main" java.lang.ArithmeticException:/by zero 
    at com.atul.security.ReThrower.c(ReThrower.java:31) 
    at com.atul.security.ReThrower.b(ReThrower.java:20) 
    at com.atul.security.ReThrower.a(ReThrower.java:10) 
    at com.atul.security.ReThrower.main(ReThrower.java:46) 

即使在與c（）打印的完整堆棧跟蹤，包括在B（）和所述系統輸出（）已經已經執行。 然而，當我再次運行它，輸出改變這樣的：

Exception caught at c 
Exception caught at b 
Exception caught at a 
java.lang.ArithmeticException:/by zero 
    at com.atul.security.ReThrower.c(ReThrower.java:31) 
    at com.atul.security.ReThrower.b(ReThrower.java:20) 
    at com.atul.security.ReThrower.a(ReThrower.java:10) 
    at com.atul.security.ReThrower.main(ReThrower.java:46) 
Exception in thread "main" java.lang.ArithmeticException:/by zero 
    at com.atul.security.ReThrower.c(ReThrower.java:31) 
    at com.atul.security.ReThrower.b(ReThrower.java:20) 
    at com.atul.security.ReThrower.a(ReThrower.java:10) 
    at com.atul.security.ReThrower.main(ReThrower.java:46) 

鑑於這是單線程的，爲什麼會出現在多個運行行爲的改變？

Answer 1

e.printStacktrace打印到System.err而您打印其餘行System.out。當你打印到兩個流the result can look out of order。