Thanks to you all for the tips !
Actually , the problem was WinRar !
However i decided to follow the hint and bought the Zechner ' s book and install libgdx .
And men have less scruple in offending one who makes himself loved,
that one who makes himself feared;
because love is held by a tie of obligation, which, because men are bad,
from each private interest is broken;
but the fear is held by a dread of punishment which never abandons.
"(Niccolo Machiavelli," The Prince ").