发表新帖
发表新帖

Java Collections using wildcard

前端 未结
关注
7 1582
天命终不由人
天命终不由人 2020-12-11 03:26 
public static void main(String[] args) {

    List mylist = new ArrayList();

    mylist.add(\"Java\"); // compile error

}
         


        
      
      
      

        

          7条回答        


        
    
                    
  • 
            
            
    
                         
                 生来不讨喜 
              
              
    
                
                   生来不讨喜
                                             
                
                
                (楼主)
            
              
                  
    
                2020-12-11 03:50
              
    

            
    
            
    
              
              

    In his book great 'Effective Java' (Second Edition) Joshua Bloch explains what he calls the producer/consumer principle for using generics. Josh's explaination should tell you why your example does not work (compile) ...
    


    Chapter 5 (Generics) is freely available here: http://java.sun.com/docs/books/effective/generics.pdf
    


    More information about the book (and the author) are available: http://java.sun.com/docs/books/effective/
    
    
    
             
    
                                                        
    
            
    
            
    
              
                
                0
              
                   
                
               讨论(0)
              
                                                  
              
              
    
                          
             
       
          
              
    
                                       
    

    

                
    
                         
          
    • 
                              			
        

        
        

          

            
            

              
              

            
    


                                 
              

            

                          
    

        
         

                
                

                  
                

                

                   看不清?
                

              

                                  

                    
   
                 
             
              
提交回复

            

          

        

      

       
      
    
    

          
 
     
 

        
热议问题