从catch块调用方法

Question

I just want to know what will happen when i call a method from catch block ,which is responsible for throwing the exception(Throws the exception). I searched hard about it but no any satisfiable answer found....

for eg.

public void A()
{
 try{
     //code which may throw exception
    }
 catch(Exception e)
  {
   A();
  }
}

Answer 1

Did you try it? Calling the method there does the same as calling it anywhere. If it returns a value, throws an exception, halts the JVM, or whatever, it'll work there just like anywhere. What you're doing is some form of recursion , where a method invokes itself. When you do that, you have to have some kind of terminating condition , or it'll go on invoking itself forever or, since you're in Java, until you run out of stack space, when you'll get a StackOverflowError .

Answer 2

Why would you like to call the same method in the catch block in which the exception is thrown?

It it keeps on throwing exceptions, then it may result in an infinite loop causing java heap space error.

You should call a method that handles that exception or takes some appropriate steps for exception.

Now for your question, you can call any method that is accessible inside your method A() inside the catch block.

public void myMethod(){

}
public void A()
{
 try{
     //code which may throw exception
 }
 catch(Exception e)
 {
   myMethod();
 }
}

Answer 3

是的，代码将陷入无限循环中，并一次又一次抛出异常。

Answer 4

//Just add like while condition  in your method 
int count = 0;
int max-attempt = 5;
while(true) {
    try {
        // Some Code
        // break out of loop, or return, on success
    } catch (Exception e) {
        // handle exception
        if (++count >= max-attempt) throw e;
    }
}

Answer 5

This will cause an infinite loop. With this code:

package com.sandbox;

public class Sandbox {

    public static void main(String[] args) {
        new Sandbox().run();
    }

    private void run() {
        try {
            throw new RuntimeException("A");
        } catch (Exception e) {
            run();
        }
    }
}

This is the exception thrown:

Exception in thread "main" java.lang.StackOverflowError
at java.lang.Exception.<init>(Exception.java:66)
at java.lang.RuntimeException.<init>(RuntimeException.java:62)
at com.sandbox.Sandbox.run(Sandbox.java:11)
at com.sandbox.Sandbox.run(Sandbox.java:13)
at com.sandbox.Sandbox.run(Sandbox.java:13)
at com.sandbox.Sandbox.run(Sandbox.java:13)

Answer 6

It will re-try the method A()

However, Till the Exception is not-occured this will keep on re-trying.

Unless Exception in this scenario is temporary one , this might cause an infinite loop.

probably the best way to do is issue a A() call on some condition / timeout.

Answer 7

You must Call a method in catch block iff you want that method to perform a specific task when an Exception is caught /thrown . Example : you may want to print the reason for an exception occured ;)

Answer 8

I had a similar requirement and tried this

public void A(Boolean callingFromCatch)
{
if(!callingFromCatch){
 try{
     //code which may throw exception
    }
 catch(Exception e)
  {
   A(true);
  }
}else{
     try{
         reloadPage();
         //try again
        }
        catch(Exception e){}
    }
}