There are multiple differences between WebClient and Java-Client. The answer can go very long and would recommend you to go through the admin guides for the same. 

In a nutshell Java-clients lets you do the administrative actions around agile e.g. all the configuration w.r.t attributes, workflow, module enabling, content services, LDAP, PX configurations, event configurations, privilege configuration etc. can be achieved via Java-Client. 

Coming to WebClient, it is preferable mode for user operation due to it’s ease of use and thin-client features. Most of the operation that you can perform  using Web-Client can be done using Java-client as well. 

The Java client is a direct descendant of the old fat client that maintains the full functionality of Agile while the web client is the thin client that tends to handle the bread and butter of functionalities.  The privileges do not care which client you use.  While you can start things like import and export from the web client, each function will take you to another client specifically for the activity you choose.  Int eh example you have provided, each client would take you to the same function.  You can find this function is the tools and settings menu…. looks like a cog in the upper left hand side.

Hi pdasanapu,

basically speaking you’ll use JavaClient to manage and configure Agile environment, it also contains the majority of features available in WebClient. I always suggest that regular users use WebClient.
There is a feature called Fileload  that you can use to load files into Agile’s objects. If you have the appropriate privileges you can reach the feature going to Tools and Settings, Fileload. Refer to the attached file to see the path.
It will be necessary to build a load file with parameters described in the Agile’s document called Agile Product Lifecycle Management Import/Export User Guide

My best
Carlos

As others have said, the Java client is intended more for administration of your Agile environment. In it you can configure basic things in the environment (URLs, File Manager, database location, etc.) as well as class and subclass attributes, workflows, events, extensions and everything else. But the data display is not as good as what is used in the web client. Since most users do not (and should not) have admin privileges, they should be using the web client when accessing your Agile environment.
 FileLoad is what should be used to attach large numbers of files. You can read how to use it in the “Using FileLoad” section of the Import/Export Guide (it is the last chapter). Note that they are in fact slightly different utilities, and so you need to consider this depending on exactly what you want to do and where the files to be attached are (the web client FileLoad will *not* attach files from the local server, and the Java client FileLoad will *not* attach files from the web proxy server [unless the drive has a network link on your server]). See the attached screen shot.
 The web client FileLoad should suffice for most needs, but you will have to coordinate getting the files you want to attach into a good location with your administrator. Also note that you MUST have the FileLoad privilege (and Discover/Read/Modify privileges on the objects you are attaching the files to) to be able to use FileLoad no matter which client you use.

Thanks all, for you kind replay.