APAR status
Closed as program error.
Error description
Error Message: An alternate hash algorithm for java.lang.String is introduced to avoid the hash collision in put/get operations of Hash related collection maps like Hashtable, HashMap, etc . Stack Trace: N/A . N/A
Local fix
N/A
Problem summary
The current hashing algorithm is more predictable and can cause hash collision in put/get operations of Hash related collection maps like Hashtable, HashMap, etc. The alternate hash implementation will avoid the hash collision by introducing a random factor. Due to the introduction of random factor, the order of retrieval of elements from the collection maps can differ when the new hash algorithm is used. As documented in the API specification, there is no guarantee as to the order of the map; in particular, it does not guarantee that the order will remain constant over time. Application should make sure that they removed any such dependency before enabling the alternate hash algorithm. By default, the new hashing algorithm is disabled. It will be in affect only when the map capacity reaches the hashing threshold which can be set using Java command line argument -Djdk.map.althashing.threshold=nn.
Problem conclusion
This defect will be fixed in: 6.0.0 SR11 6.0.1 SR3 7.0.0 SR2 . The JDK has been equipped with an alternate hash implementation which avoids the hash collision in put/get operations of Hash related collection maps.
Temporary fix
Comments
APAR Information
APAR number
IV25852
Reported component name
JAVA CLASS LIBS
Reported component ID
620700130
Reported release
600
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2012-08-07
Closed date
2012-08-07
Last modified date
2012-11-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
JAVA CLASS LIBS
Fixed component ID
620700130
Applicable component levels
R600 PSY
UP
R700 PSY
UP
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Document Information
Modified date:
02 November 2012