I developed a project which contains all data adapters and 1 meta data Adapter, I also exported this project to a JAR file. The question is : "Could I have multiple <data_provider> tags in one adapters.xml file ?" It looks like this:

<?xml version="1.0"?>
<adapters_conf id="MYADAPTER_ID">
<metadata_provider>
<adapter_class>com.xyz.myMetaAdapter</adapter_class>
.......
</metadata_provider>

<data_provider>
<adapter_class>com.xyz.myDataAdapter1</adapter_class>
<param name="xy1">xy</param>
</data_provider>

<data_provider>
<adapter_class>com.xyz.myDataAdapter2</adapter_class>
<param name="xy2">xy2</param>
</data_provider>

<data_provider>
<adapter_class>com.xyz.myDataAdapter3</adapter_class>
<param name="xy3">xy3</param>
</data_provider>
.
.
.
.
</adapters_conf>

Thank you very much