object.equals java - Brave Search

Objects.equals and Object.equals

stackoverflow.com › questions › 34486832 › objects-equals-and-object-equals

The difference is the Objects.equals() considers two nulls to be "equal". The pseudo code is:

if both parameters are null or the same object, return true
if the first parameter is null return false
return the result of passing the second parameter to the equals() method of the first parameter

This means it is "null safe" (non null safe implementation of the first parameter’s equals() method notwithstanding).

Answer from Bohemian on Stack Overflow

docs.oracle.com › javase › 8 › docs › api › java › lang › Object.html

Object (Java Platform SE 8 )

April 21, 2026 - The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

medium.com › @AlexanderObregon › javas-objects-equals-method-explained-3a84c963edfa

Java’s Objects.equals() Method Explained | Medium

February 23, 2026 - Explore Java's Objects.equals() method, a null-safe solution for object comparison. Learn how it prevents NullPointerException and simplifies your code.

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stackoverflow.com › questions › 34486832 › objects-equals-and-object-equals

java - Objects.equals and Object.equals - Stack Overflow

The difference is the Objects.equals() considers two nulls to be "equal". The pseudo code is:

if both parameters are null or the same object, return true
if the first parameter is null return false
return the result of passing the second parameter to the equals() method of the first parameter

This means it is "null safe" (non null safe implementation of the first parameter’s equals() method notwithstanding).

this is literal code from java source: as you can see, @Agent_L is right

reddit.com › r/learnjava › confused on how equals() method works for objects and strings.

r/learnjava on Reddit: Confused on how equals() method works for objects and strings.

November 17, 2018 -

//Suppose I have another class with a default constructor method

public Circle(double r)

{

radius =r;

}

//and in my main class I have the codes

Circle cir1= new Circle(5.1);

Circle cir2= new Circle(5.1);

System.out.println(cir1.equals(cir2));

// Why would the output be false? If i use the equals() method to compare the content of two strings, then why wouldnt it work the same way when comparing the contents with two different objects? How is the output false if the arguments are the same?

The default implementation of equals does an object comparison, so your cir1.equals... is checking to see if they're the same (not just the same values). String, for instance, overrides the default equals method to check against the value not the object itself. You can override the equals method on your circle object to compare based on value (radius). More info

First of all, the objects aren't "the same" (which is why the default equals method returns false). They live in different places in memory so they the computer treats them as different objects. However, they are "equal." If you want the equals method to check for that equality then you have to implement it yourself. Here is some very bad code that isn't going to compile but maybe it's demonstrative anyway: public class Circle { private double radius; public Circle(double aRadius) { radius = aRadius; } public boolean equals(Circle c) { return this.radius == c.radius; } } The idea is that you have to tell the compiler what it should mean for two circles to be equal. In this case, you want to check that the radii are equal. That code is bad for several reasons, though. First, the equals method must take an Object as its argument (because you're overriding another method). Second, c.radius isn't going to work because radius is private (or at least it should be). Third, it is bad practice to check equality of doubles (more on this in a bit). Here is better code: public class Circle { private double radius; public Circle(double aRadius) { radius = aRadius; } public boolean getRadius() { return radius; } public boolean equals(Object o) { // this checks if this object and o are *actually* the same. if (o == this) { return true; } // Here we return false if o isn't actually a Circle object. if (!(o instanceof Circle)) { return false; } // If the code gets to this point we can safely assume that o is actually // a circle and we can do the radius check. Circle c = (Circle) o; return radius == c.getRadius(); } } The code above should do what you're describing but I still didn't address the "it is bad practice to check equality of doubles" issue. The problem is that the line return radius == c.getRadius(); isn't really going to work how you think. There is a lot of rounding involved in floating point computations and sometimes numbers that you think should be equal aren't going to be equal. There are several ways to handle this but the general idea is that you should invent some kind of "tolerance" where doubles that are within the tolerance of each other are considered equal. Something like this: Circle c = (Circle) o; double difference = radius - c.getRadius(); return (difference < 0.000000000001) && (difference > -0.000000000001); This code checks that the difference between radius and c.getRadius() is between 0.000000000001 and -0.000000000001. This still isn't the best; you shouldn't use a magic number like 0.000000000001 (instead there should be a global TOLERANCE variable) and there are already methods in the world to handle the comparison of doubles so it's probably better to use one of those but this isn't a thread about comparing doubles so I won't get into it any further.

cloudbees.com › blog › benchmarking-different-approaches-equality-java

Benchmarking Different Approaches to Equality in Java

At some point, however, you will come to a decision and decide that two objects are equal if a defined list of properties of the object are equal. Now the time has come to actually write the equals(Object) method.

infoworld.com › home › blogs › java challengers

Comparing Java objects with equals() and hashcode() | InfoWorld

May 16, 2024 - Java’s equals() and hashcode() are two methods that work together to verify if two objects have the same value.

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docs.oracle.com › javase › 8 › docs › api › java › util › Objects.html

Objects (Java Platform SE 8 )

April 21, 2026 - Otherwise, equality is determined by using the equals method of the first argument. ... Returns the hash code of a non-null argument and 0 for a null argument. ... Generates a hash code for a sequence of input values. The hash code is generated as if all the input values were placed into an ...

reddit.com › r/javahelp › how does java "==" operator check equality between objects? trying to understand how object.equals() works

r/javahelp on Reddit: How does Java "==" operator check equality between objects? Trying to understand how Object.equals() works

January 8, 2023 -

I'm wondering how "==" is implemented to check equality between two objects. The internet say's the Object superclass, .equals() is defined as:

public boolean equals(Object obj) {
   return (this == obj);
}

How does a simple "==" check equality between two objects? Hashcode, a bitwise AND of the sum of all data? I can't find anywhere that explains in depth how two objects are compared.

== checks the Object references. It only yields true if both variables point to the same object in memory. It does not check any field values.

im pretty sure it checks if the two objects point to the same memory location (basically if theyre both one in the same, literally) someone pls correct me if im wrong

geeksforgeeks.org › java › equals-hashcode-methods-java

equals() and hashCode() methods in Java - GeeksforGeeks

July 23, 2025 - equals() method In java equals() method is used to compare equality of two Objects.

medium.com › dev-java › java-best-practice-why-and-should-not-replace-equals-for-object-comparison-834cd7ccb0a9

Java Best Practice: Why == and != Should Not Replace equals() for Object Comparison | by Anil R | Dev Java | Medium

April 28, 2025 - Java Best Practice: Why == and != Should Not Replace equals() for Object Comparison n Java, developers often use == and != to compare objects, but this can lead to subtle bugs and incorrect program …

geeksforgeeks.org › java › java-program-to-compare-two-objects

Java Program to Compare Two Objects - GeeksforGeeks

July 23, 2025 - Therefore, it is advisable not to use this method in comparing objects without overriding it. Implementing the equals method for the before example: ... // Java Program to Compare Two Objects import java.io.*; class Pet { String name; int age; String breed; Pet(String name, int age, String breed) { this.name = name; this.age = age; this.breed = breed; } @Override public boolean equals(Object obj) { // checking if the two objects // pointing to same object if (this == obj) return true; // checking for two condition: // 1) object is pointing to null // 2) if the objects belong to // same class o

programiz.com › java-programming › library › object › equals

Java Object equals()

The equals() method takes a single parameter. obj - object which is to be compared with the current object ... Note: In Java, if two reference variables refer to the same object, then the two reference variables are equal to each other.

medium.com › @sunil17bbmp › mastering-equals-and-hashcode-in-java-a-complete-guide-to-object-identity-c147d23d6c2c

Mastering equals() and hashCode() in Java: A Complete Guide to Object Identity | by Code With Sunil | Code Smarter, not harder | Medium

September 27, 2025 - In Java, the equals() and hashCode() methods are defined in the Object class, which means every Java class inherits a default implementation of these methods.

geeksforgeeks.org › java › java-equals-compareto-equalsignorecase-and-compare

Java | ==, equals(), compareTo(), equalsIgnoreCase() and compare() - GeeksforGeeks

January 22, 2026 - The == operator compares object references, not the actual content of the strings. It returns true only if both references point to the same memory location.Strings created without the new keyword are stored in the String Constant Pool, so they ...

docs.aws.amazon.com › AWSJavaSDK › latest › javadoc › com › amazonaws › services › elasticloadbalancing › model › SetLoadBalancerPoliciesForBackendServerResult.html

SetLoadBalancerPoliciesForBackendServerResult (AWS SDK for Java - 1.12.797)

@Generated(value="com.amazonaws:aws-java-sdk-code-generator") public class SetLoadBalancerPoliciesForBackendServerResult extends AmazonWebServiceResult<ResponseMetadata> implements Serializable, Cloneable · Contains the output of SetLoadBalancerPoliciesForBackendServer. ... Returns a string representation of this object...

docs.oracle.com › javase › 8 › docs › api › java › util › ArrayList.html

ArrayList (Java Platform SE 8 )

April 21, 2026 - public boolean contains(Object o) Returns true if this list contains the specified element. More formally, returns true if and only if this list contains at least one element e such that (o==null ? e==null : o.equals(e)).

tc39.es › ecma262

ECMAScript® 2027 Language Specification

1 week ago - ECMAScript 2021, the 12th edition, introduced the replaceAll method for Strings; Promise.any, a Promise combinator that short-circuits when an input value is fulfilled; AggregateError, a new Error type to represent multiple errors at once; logical assignment operators (??=, &&=, ||=); WeakRef, for referring to a target object without preserving it from garbage collection, and FinalizationRegistry, to manage registration and unregistration of cleanup operations performed when target objects are garbage collected; separators for numeric literals (1_000); and Array.prototype.sort was made more precise, reducing the amount of cases that result in an

docs.aws.amazon.com › AWSJavaSDK › latest › javadoc › com › amazonaws › services › elasticloadbalancing › model › EnableAvailabilityZonesForLoadBalancerResult.html

EnableAvailabilityZonesForLoadBalancerResult (AWS SDK for Java - 1.12.797)

Returns a string representation of this object. This is useful for testing and debugging.

docs.aws.amazon.com › AWSJavaSDK › latest › javadoc › com › amazonaws › services › glacier › model › PurchaseProvisionedCapacityResult.html

PurchaseProvisionedCapacityResult (AWS SDK for Java - 1.12.797)

Returns a reference to this object so that method calls can be chained together.

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How do you implement the equals and hashCode methods in Java to ensure object equality?

April 17, 2023 - Identity means that two objects are the same instance, which can be checked with the == operator. Equality means that two objects have the same state or value, which can be checked with the equals method.