In, AutowireUtils.sortConstructors(), Using valueOf is faster than using constructor [SPR-12385]

[spring-projects-issues]

Kang Baek-Kyu opened SPR-12385 and commented

Using valueOf is approximately 3.5 times faster than using constructor

Because Using new Integer(int) is guaranteed to always result in a new object whereas Integer.valueOf(int) allows caching of values to be done by the compiler, class library, or JVM.

So changed source like this

return (new Integer(c1pl)).compareTo(c2pl) * -1;
==>return (Integer.valueOf(c1pl)).compareTo(c2pl) * -1;

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Affects: 4.1.1

Reference URL: #682

Referenced from: commits 4945cf1

[spring-projects-issues]

Juergen Hoeller commented

Good catch! However, there's an even more efficient way of expressing this:

return (c1pl < c2pl ? 1 : (c1pl > c2pl ? -1 : 0));

analogous to the Integer.compare(int, int) method in Java 7. I've applied this change to both constructor and factory method sorting for 4.1.2 now.

Juergen

[spring-projects-issues]

Juergen Hoeller commented

I've also applied analogous changes to ReflectiveConstructorResolver and ReflectiveMethodResolver in SpEL.

Juergen

[spring-projects-issues]

Kang Baek-Kyu commented

Aha. Hou did not know that there is a new way.
Thanks, Juergen.