Accesing Login User Details

1- Using Groovy: We can set default expression in view object attribute as below

adf.context.securityContext.getUserPrincipal().getName()
or
adf.context.securityContext.getUserName()

2- Java Code: You can get User Name in Java code also using the following code.

     ADFContext adfCtx = ADFContext.getCurrent();
     SecurityContext secCntx = adfCtx.getSecurityContext();
     String user = secCntx.getUserPrincipal().getName();
     String _user = secCntx.getUserName();

3-Expression Language: You can bind ADF Faces componenets with the following EL to get logged User Name.

 #{securityContext.userName}

Source:http://mahmoudoracle.blogspot.in/2012/06/adf-get-current-logged-user-name.html#.UmTBMPlHK8w