LB40 LB40 - 1 year ago 131
Java Question

New Integer vs valueOf

I was using Sonar to make my code cleaner, and it pointed out that I'm using

new Integer(1)
instead of
. Because it seems that
does not instantiate a new object so is more memory-friendly. How can
not instantiate a new object? How does it work? Is this true for all integers?

Answer Source

Integer.valueOf implements a cache for the values -128 to +127. See the last paragraph of the Java Language Specification, section 5.1.7, which explains the requirements for boxing (usually implemented in terms of the .valueOf methods).

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