I am new in using winrunner, i have some doubts. like what is the scripting language most commonly used to script in winrunner, is the winunner TSL used commonly or some other language?

To test Java applications what are the addin we hav to include?
Is winrunner used only to test the backend of an application or both back & frontend?

Can we use C while scripting?
If so to which extent can we use?