//before
if (ballPos.x > playerPos.x+playerPaddle.getWidth()/2 && ballPos.x < playerPos.x+playerPaddle.getWidth()
        && ballPos.y < playerPos.y+playerPaddle.getHeight() && ballPos.y > playerPos.y-(playerPaddle.getHeight()/2)){
    ballDirection.x *= -1;
}

//after
if (playerBox.contains(ballBox)){
    ballDirection.x *= -1;
}