check two objects are the same according to their property in JAVA -

check two objects are the same according to their property in JAVA -

for example:

public class fruit{ private string color; private double weight; ... public boolean equals(fruit a){ homecoming (this.getcolor().equals(a.getcolor()) && (this.getweight()==a.getweight())); } } public class orange extends fruit{ public orange(double weight) { super("orange", weight); } } public class navalorange extends orange{ public navalorange(double weight) { super(weight); } }

then wrote test check 2 objects if same.

orange orange = new orange(8); navalorange navalorange = new navalorange(8); assertequals(orange, navalorange);

but keeps returning errors:

junit.framework.assertionfailederror: expected:<orange@5305068a> was:<navalorange@1f32e575>

can explain why happening? think may wrong @ tostring method.

there no equals(fruit) method in object. equals method should start like...

@override public boolean equals(object a) { boolean equals = false; if (a instanceof fruit) { ... } homecoming equals; }

basically, assertequals doing using object#equals. can test adding @override annotation equals method , produce compiler error, `equals(fruit) not override method it's parent...

also, if override equals, should override hashcode in order maintain it's contract...

from javadocs object#equals

note necessary override hashcode method whenever method overridden, maintain general contract hashcode method, states equal objects must have equal hash codes.

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