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From "Knut Anders Hatlen (JIRA)" <j...@apache.org>
Subject [jira] [Created] (DERBY-5873) Avoid unnecessary allocation of Number instances in client/server
Date Mon, 23 Jul 2012 10:01:34 GMT
Knut Anders Hatlen created DERBY-5873:

             Summary: Avoid unnecessary allocation of Number instances in client/server
                 Key: DERBY-5873
                 URL: https://issues.apache.org/jira/browse/DERBY-5873
             Project: Derby
          Issue Type: Improvement
          Components: Network Client, Network Server
    Affects Versions:
            Reporter: Knut Anders Hatlen
            Assignee: Knut Anders Hatlen

Java 5 introduced some new static factory methods (called valueOf()) in the Number sub-classes,
to be used in preference of the constructors unless a fresh instance is required. The valueOf()
methods are allowed to cache and reuse objects, possibly reducing the allocation/gc cost and
the memory footprint. For example, Integer.valueOf(int) uses a pre-allocated cache for values
between -128 and +127 by default (the cache size can be tuned with JVM flags).

Now that the server and client code is compiled against Java 5 libraries, we should use the
valueOf() methods  to get those benefits. Note also that Java 5 auto-boxing of numbers uses
these methods implicitly, so in many cases we can just remove the calls to the constructor
and the compiler will automatically insert the calls for us.

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