1 2 | public boolean equals(Object obj) public int hashCode() |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | import java.util.HashMap; public class Apple { private String color; public Apple(String color) { this.color = color; } public boolean equals(Object obj) { if (!(obj instanceof Apple)) return false; if (obj == this) return true; return this.color == ((Apple) obj).color; } public static void main(String[] args) { Apple a1 = new Apple("green"); Apple a2 = new Apple("red"); //hashMap stores apple type and its quantity HashMap m = new HashMap(); m.put(a1, 10); m.put(a2, 20); System.out.println(m.get(new Apple("green"))); } } |
1 2 3 | public int hashCode(){ return this.color.length(); } |
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