Did you remove the following line from your code?
BewegendePlattform(200, 700);
BewegendePlattform(200, 700);
public void mitbewegen()
{
minimumX = 200;
maximumX = 700;
direction = 1;
if(aufBewegendePlattform())
{
if(getX() <= minimumX) direction = 1;
if(getX() >= maximumX) direction = -1;
setLocation(getX() + direction, getY());
}
else
{
Bewegen();
}
}