how can I return the child variable in an extended base method with Java oop

public class Buildings {
public int getLevel(){
    return level;
}
}
 public class MainBuilding extends Buildings{
public static final int cost = 200;
public static int  level = 1;
}
MainBuilding main = new MainBuilding();
main.getLevel();

I want have several building with diffrent instantsvaribles like level and cost but they should have the same method getLevel() that just returns the level. I can't find how I can do these with java...

Either move the level variable (which should probably be an instance variable, rather than a static variable) to Buildings or make getLevel() abstract so that each subclass has to implement it separately (whether that's by returning a variable, or just always returning a constant, or whatever - that's an implementation detail).

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