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Groups > comp.lang.java.programmer > #5723

The behavior of "equals" method of Arrays.asList() implementation

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Basically I wonder if it is safe to use equals for collections (and
junit's assertEquals in particular which in fact results in the
*.equals invocation).

One of collection instances I am working with is returned from
Arrays.asList(..) method invocation.
Sun JDK sources defines no equals method for
java.util.Arrays.ArrayList inner class so I guess it is not safe to
compare collections in that way.
Surprisingly, equals called from Arrays.ArrayList "magically" (I can't
find another word) checks the elements in the collection!
I tried to walk throug the sources by using "step into" in the
debugger, but it mysteriously transfer control to the equals method of
my class (and yes, I have JDK sources attached, e.g. I can walk
through implementation of certain String method).

So the first question is: whether it is safe to use equals for *all*
the JDK's collections?
The second question is whether JVM adds "hidden" implementation in
certain places and Arrays helper List implementation is one of those,
so I may expect Arrays.asList(...) implementation behave in the same
way on different JDKs?

Thanks in advance!

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The behavior of "equals" method of Arrays.asList() implementation Alex J <vstrength@gmail.com> - 2011-06-28 02:19 -0700
  Re: The behavior of "equals" method of Arrays.asList() implementation Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-06-28 07:08 -0400
    Re: The behavior of "equals" method of Arrays.asList() implementation Lew <noone@lewscanon.com> - 2011-06-28 07:29 -0400
  Re: The behavior of "equals" method of Arrays.asList() implementation Roedy Green <see_website@mindprod.com.invalid> - 2011-06-28 10:04 -0700

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