两段java代码的比较

import java.util.ArrayList;   
import java.util.List;   
  
public class TailRecursionTest {   
    public static void main(String[] args) {   
        TailRecursionTest t = new TailRecursionTest();   
        t.a(0);   
    }   
  
    public void a(int j) {   
        System.out.println(j);   
        j++;   
        if (j<10000)  //if (j!=10000) 也可以
            return;   
        List list = new ArrayList<Integer>(100000);   
        
        a(j);   
    }   
}