[jira] Resolved: (HARMONY-206) HashMap's behavior is non-compliant with RI when key is reused

["Nathan Beyer (JIRA)" <ji...@apache.org>]

     [ http://issues.apache.org/jira/browse/HARMONY-206?page=all ]
     
Nathan Beyer resolved HARMONY-206:
----------------------------------

    Resolution: Fixed

> HashMap's behavior is non-compliant with RI when key is reused
> --------------------------------------------------------------
>
>          Key: HARMONY-206
>          URL: http://issues.apache.org/jira/browse/HARMONY-206
>      Project: Harmony
>         Type: Bug

>   Components: Classlib
>     Reporter: Paulex Yang
>     Assignee: Tim Ellison
>     Priority: Minor
>  Attachments: java.util.patch, tests.api.java.util.patch
>
> As discussion in mailing list,  when hash key is reused by modify its hashcode, Harmony's HashMap show different behavior with RI.  There are some ways to mimic RI's behavior, including rehash the hash of key, and cache the hash when key/value pair is put into. I will attach patches soon.
> Test case:
> public class HashMapTest { 
> public static void main(String[] args) { 
> 	ReusableKey k = new ReusableKey(); 
> 	HashMap map = new HashMap(); 
> 	k.setKey(1); 
> 	map.put(k, "value1"); 
> 	k.setKey(18); 
> 	System.out.println(map.get(k)); 
> 	k.setKey(17); 
> 	System.out.println(map.get(k)); 
> 	} 
> } 
> class ReusableKey{ 
> 	private int key = 0; 
> 	public void setKey(int key){ 
> 		this.key = key; 
> 	} 
> 	public int hashCode(){ 
> 		return key; 
> 	} 
> 	public boolean equals(Object o){ 
> 		if(o == this){ 
> 			return true; 
> 		} 
> 		if(!(o instanceof ReusableKey)){ 
> 			return false; 
> 		} 
> 		return key == ((ReusableKey)o).key; 
> 	} 
> } 
> RI 5.0 output:
>   null 
>   null 
> Harmony output:
>   null 
>   value1 

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