方法重载时的重复方法 [英] Duplicate Method while Method-Overloading

问题描述

以下代码给出编译错误，错误为Duplicate Method。

  static int test（int i）{
返回1; 
} 
 
 static String test（int i）{
 returnabc; 
} 
  

这是预期的，因为重载方法都具有相同的签名并且仅在返回类型。

但是下面的代码可以很好地编译，并带有警告：

  static int test1（List< Integer> l）{
 return 1; 
 
 
 static String test1（List< String> l）{
 returnabc; 
 
 
 
 
 
 $ b 
因为我们知道Java泛型可以在Erasure上工作，代码，这两种方法具有完全相同的签名，并且与返回类型不同。 
 
 
 
 Furthur，令我惊讶的是下面的代码再次给出了编译错误：
 
 
  static int test1（List< Integer> l）{
 return 1; 
} 
 
 static String test1（List l）{
 returnabc; 
 
  
第二个代码是如何工作的，没有发生任何编译错误，尽管存在重复的方法？解决重载的方法是在编译时而不是运行时完成的，所以Java编译器会知道它们之间的差异在你的第二个例子中的两个之间。在第三个例子中，问题是 List< Integer> 也是 List ，所以它不会如果您传入 List< Integer> ，则知道使用哪一个。
 
Following code gives compilation error with error "Duplicate Method"
static int test(int i){
     return 1;
}

static String test(int i){
     return "abc";
}
This is expected as both the overloaded method have same signature and differ only in return type.

But the following code compiles fine with a warning:
static int test1(List<Integer> l){
    return 1;
}

static String test1(List<String> l){
    return "abc";
}
As, we know the Java Generics works on Erasure, which mean in byte-code, both these method have exactly the same signature and differs with return type. 

Furthur, to my surprise the following code again gives compilation error:
static int test1(List<Integer> l){
    return 1;
}

static String test1(List l){
    return "abc";
}
How is the second code working fine without giving any compilation error, though there is duplicate method?
解决方案
Resolving overloaded methods is done at compile-time, rather than runtime, so the Java compiler would know the difference between the two in your second example. In your third example, the problem is that a List<Integer> is also a List, so it wouldn't know which one to use if you passed in a List<Integer>.

                        
这篇关于方法重载时的重复方法的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！