Double values not adding properly

Question

i got this class where i have to define a map< Integer,Double >

public class ExpConfig {

    public static final int LEVEL_MIN = 1;
    public static final int LEVEL_MAX = 100;
    public static final int FACTOR = 50;
    public static final double BASE_EXPONENT = 1.8D;

    public static int level = LEVEL_MIN;
    public static double exponent = BASE_EXPONENT;

    private static final Map<Integer, Double> myMap;
    static {
        Map<Integer, Double> aMap = new LinkedHashMap<Integer,Double>();
        aMap.put(20, 0.01D);//From level 1 to 20
        aMap.put(50, 0D);//From level 21 to 50
        aMap.put(100, 0.01D);//From level 51 to 100
        myMap = Collections.unmodifiableMap(aMap);
    }

    ExpConfig(){
        populateExponentMap();
    }

    private void populateExponentMap()
    {
        Map<Integer, Double> exponentMap = new LinkedHashMap<Integer,Double>();

        ExpConfig.myMap.forEach((k,v)-> {
            for(int counter=level;counter<=k;counter++,level++){
                exponent+=v;
                exponentMap.put(level, exponent);
                System.out.println(level + " : " + exponent);
            }        
        });  
    }

    //@TestMethod Run As Java Application
    public static void main(String[] args) throws IOException
    {
        ExpConfig asd = new ExpConfig();
    }
}

when i run the class as java application, i the construction i got a System.out.Print that verify the map values.

but actually the values are not expected.

1 : 1.8
2 : 1.81
3 : 1.82
4 : 1.83
5 : 1.84
6 : 1.85
7 : 1.86
8 : 1.87
9 : 1.8800000000000001
10 : 1.8900000000000001
11 : 1.9000000000000001
12 : 1.9100000000000001
13 : 1.9200000000000002
14 : 1.9300000000000002
15 : 1.9400000000000002
16 : 1.9500000000000002
17 : 1.9600000000000002
18 : 1.9700000000000002
19 : 1.9800000000000002
20 : 1.9900000000000002
21 : 1.9900000000000002
22 : 1.9900000000000002
23 : 1.9900000000000002
24 : 1.9900000000000002
25 : 1.9900000000000002
26 : 1.9900000000000002
27 : 1.9900000000000002
28 : 1.9900000000000002
29 : 1.9900000000000002
30 : 1.9900000000000002
31 : 1.9900000000000002
32 : 1.9900000000000002
33 : 1.9900000000000002
34 : 1.9900000000000002
35 : 1.9900000000000002
36 : 1.9900000000000002
37 : 1.9900000000000002
38 : 1.9900000000000002
39 : 1.9900000000000002
40 : 1.9900000000000002
41 : 1.9900000000000002
42 : 1.9900000000000002
43 : 1.9900000000000002
44 : 1.9900000000000002
45 : 1.9900000000000002
46 : 1.9900000000000002
47 : 1.9900000000000002
48 : 1.9900000000000002
49 : 1.9900000000000002
50 : 1.9900000000000002
51 : 2.0
52 : 2.01
53 : 2.0199999999999996
54 : 2.0299999999999994
55 : 2.039999999999999
56 : 2.049999999999999
57 : 2.0599999999999987
58 : 2.0699999999999985
59 : 2.0799999999999983
60 : 2.089999999999998
61 : 2.099999999999998
62 : 2.1099999999999977
63 : 2.1199999999999974
64 : 2.1299999999999972
65 : 2.139999999999997
66 : 2.149999999999997
67 : 2.1599999999999966
68 : 2.1699999999999964
69 : 2.179999999999996
70 : 2.189999999999996
71 : 2.1999999999999957
72 : 2.2099999999999955
73 : 2.2199999999999953
74 : 2.229999999999995
75 : 2.239999999999995
76 : 2.2499999999999947
77 : 2.2599999999999945
78 : 2.2699999999999942
79 : 2.279999999999994
80 : 2.289999999999994
81 : 2.2999999999999936
82 : 2.3099999999999934
83 : 2.319999999999993
84 : 2.329999999999993
85 : 2.3399999999999928
86 : 2.3499999999999925
87 : 2.3599999999999923
88 : 2.369999999999992
89 : 2.379999999999992
90 : 2.3899999999999917
91 : 2.3999999999999915
92 : 2.4099999999999913
93 : 2.419999999999991
94 : 2.429999999999991
95 : 2.4399999999999906
96 : 2.4499999999999904
97 : 2.45999999999999
98 : 2.46999999999999
99 : 2.4799999999999898
100 : 2.4899999999999896

the key is correct but the value is not, the expected result would be with only 2 decimal numbers.

I know the solution is rounding the values, but why is this happening?