java - Comparing an object with a String using equals() method -

in below example, expecting equals() return true:

public class flower {     string flower;     public flower (string flower) {         this.flower = flower;     }      public static void main(string[] args) {         flower 1 = new flower("flower");         boolean issame = false;         if(one.equals("flower")) {             issame = true;         }         system.out.print(issame);     } }  

however, result false... because i'm comparing object string? read equals() method , said compare strings objects. why getting result false although same?

the short answer: need override implementation of equals() in flower (note: capital f) class. like do:

@override public boolean equals(object o) {     return (o instanceof flower && ((flower)o).flower.equals(flower)) ||                 (o instanceof string && o.equals(flower)); }  @override public int hashcode() {     return flower.hashcode(); } 

overriding hashcode() equals() form: generally, 'attributes' (e.g. fields) pick doing equals() should used in hashcode() calculation too. in layman terms, should 'agree' each other.

the big/major/severe problem, pointed out practically here presume, equals() meant symmetric:

it symmetric: non-null reference values x , y, x.equals(y) should return true if , if y.equals(x) returns true.

and unfortunately flower class, string.equals(object) defined as such:

the result true if , if argument not null , string object represents same sequence of characters object. (emphasis mine)

this means no string ever return true when pass flower object equals().

sure, can still go against convention, you'll run bugs - minor or major - when learn more language, e.g. collection classes.

therefore: avoid such comparisons equals().