When data is entered in TextArea ( just type one line of text ). Press Home / End end . You can observe that cursor move to the first & last of the same line. Just repeate the same process by pressing Page Up & Page Down. The same type of action is performed as with Home/End key.

Actually the cursor should remain in the same place , where the cursor was last positioned i,e before the action performed using Page Up & Page Down.

I have even checked with java 5.0 . I have found the same action .

I have used build 59 (b59 ) & it is at this location.
/net/sqindia/export/disk09/jdk/1.6.0/b59/binaries/solsparc/bin.