Creating a pseudo folder with the same name of one object at the same level would overwrite the object into a folder

You may have to describe this a bit better. Also, please note that there are no actual folders in Swift. There is the concept of pseudo folders, but that is based on the names of objects.

Swift has accounts at the topmost level, then containers within an account, then a flat list of objects within a container. Imagine this list of objects in a container:

one
one/a
one/a/1/i
two/b/2/ii

This is four objects in a flat list. Pseudo directories are understood as

one/
one/a/
one/a/1/
two/
two/b/
two/b/2/

But these aren't actual objects, they're just pseudo directories based on the names of objects that do exist.

I added some detail description

Maybe it's a problem with the bindings? I tried what you described using curl and found no problems:

$ curl -XPUT http://127.0.0.1:8080/v1/AUTH_test/test -Hx-auth-token:AUTH_tkc747c5256d6a473fbf3d710ea5775e5d
201 Created

$ curl -XPUT http://127.0.0.1:8080/v1/AUTH_test/test/psuedo-1/ -Hcontent-type:application/directory -Hcontent-length:0 -Hx-auth-token:AUTH_tkc747c5256d6a473fbf3d710ea5775e5d
201 Created

$ curl -XPUT http://127.0.0.1:8080/v1/AUTH_test/test/file-1 -Hcontent-type:text/plain --data-binary '1234' -Hx-auth-token:AUTH_tkc747c5256d6a473fbf3d710ea5775e5d
201 Created

$ curl -XPUT http://127.0.0.1:8080/v1/AUTH_test/test/pseudo-1 -Hcontent-type:text/plain --data-binary 'abcd' -Hx-auth-token:AUTH_tkc747c5256d6a473fbf3d710ea5775e5d
201 Created

$ curl -XPUT http://127.0.0.1:8080/v1/AUTH_test/test/file-1/ -Hcontent-type:application/directory -Hcontent-length:0 -Hx-auth-token:AUTH_tkc747c5256d6a473fbf3d710ea5775e5d
201 Created

$ curl 'http://127.0.0.1:8080/v1/AUTH_test/test?format=json' -Hx-auth-token:AUTH_tkc747c5256d6a473fbf3d710ea5775e5d | python -mjson.tool
[
    {
        "bytes": 4,
        "content_type": "text/plain",
        "hash": "81dc9bdb52d04dc20036dbd8313ed055",
        "last_modified": "2012-07-31T01:51:20.844560",
        "name": "file-1"
    },
    {
        "bytes": 0,
        "content_type": "application/directory",
        "hash": "d41d8cd98f00b204e9800998ecf8427e",
        "last_modified": "2012-07-31T01:52:32.763770",
        "name": "file-1/"
    },
    {
        "bytes": 4,
        "content_type": "text/plain",
        "hash": "e2fc714c4727ee9395f324cd2e7f331f",
        "last_modified": "2012-07-31T01:51:53.382290",
        "name": "pseudo-1"
    },
    {
        "bytes": 0,
        "content_type": "application/directory",
        "hash": "d41d8cd98f00b204e9800998ecf8427e",
        "last_modified": "2012-07-31T01:50:02.712670",
        "name": "psuedo-1/"
    }
]

I noticed that when you create new pseudo folder, you have a "/" after the folder's name, I tried without the slash and got following result, as you can see without the slash the pseudo folder get overwritten. Does this mean the pseudo folder's name must be followed by a "/" ?

create a new container:

curl -XPUT http://10.211.55.102:8080/v1/AUTH_test/test -Hx-auth-token:d94abbc396094eeaa02da16cdbab5fbb

add new pseudo folder
curl -XPUT http://10.211.55.102:8080/v1/AUTH_test/test/psuedo-1 -Hcontent-type:application/directory -Hcontent-length:0 -Hx-auth-token:d94abbc396094eeaa02da16cdbab5fbb

list objects:
curl http://10.211.55.102:8080/v1/AUTH_test/test?format=json -Hx-auth-token:d94abbc396094eeaa02da16cdbab5fbb | python -mjson.tool

    {
        "bytes": 0,
        "content_type": "application/directory",
        "hash": "d41d8cd98f00b204e9800998ecf8427e",
        "last_modified": "2012-08-01T18:11:04.739910",
        "name": "psuedo-1"
    }

add a file with the same name as the pseudo folder:
curl -XPUT http://10.211.55.102:8080/v1/AUTH_test/test/psuedo-1 -Hcontent-type:text/plain --data-binary '1234' -Hx-auth-token:d94abbc396094eeaa02da16cdbab5fbb

list the objects:
curl http://10.211.55.102:8080/v1/AUTH_test/test?format=json -Hx-auth-token:d94abbc396094eeaa02da16cdbab5fbb | python -mjson.tool
    {
        "bytes": 4,
        "content_type": "text/plain",
        "hash": "81dc9bdb52d04dc20036dbd8313ed055",
        "last_modified": "2012-08-01T18:13:45.011280",
        "name": "psuedo-1"
    }

This is not a bug and Swift is working as intended. For more information on pseudo-directories, look at http://docs.openstack.org/api/openstack-object-storage/1.0/content/pseudo-hierarchical-folders-directories.html