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Exemplification changes (#33903)

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* Exemplification

Provided more comments on the coding portions to show what each line does in respect to the program. Also specified what happens when "==" is used when the "equals()" method should be employed.

* Formatting
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BoopMehNose
2019-03-23 06:36:56 -04:00
committed by The Coding Aviator
parent 9064182770
commit c7f8f8f75a
1 changed files with 10 additions and 8 deletions
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16
guide/english/java/equality/index.md
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@ -47,7 +47,7 @@ The `if` statement will cause an error. It is important to remember that a sing
The built-in `Object` class in Java, which all other classes automatically extend, contains a number of helpful built-in methods. One such method is `equals()`, which takes another object as its argument and returns whether the two objects should be considered "equal" according to the relevant logic for that class. The built-in `Object` class in Java, which all other classes automatically extend, contains a number of helpful built-in methods. One such method is `equals()`, which takes another object as its argument and returns whether the two objects should be considered "equal" according to the relevant logic for that class.
The 'String' class is one of the most common examples of a class that overrides the `equals()` method. When comparing two 'String's for equality, you need to use the `equals()` method, as `==` won't work as you expect. The 'String' class is one of the most common examples of a class that overrides the 'equals()' method. When comparing two 'String's for equality, you need to use the 'equals()' method, as '==' won't work as you expect. Instead of returning 'true' when comparing objects, the '==' operator will continuously return 'false' unless the objects being compared are the *same object*.
```java ```java
String s1 = "Bob"; String s1 = "Bob";
@ -59,16 +59,18 @@ System.out.println(s1.equals(s2)); //true
When you create a new class in Java, you will often want to override the `equals()` method in order to provide a more meaningful way to compare two objects of the same class. How this method is implemented is completely up to the developer's judgement. When you create a new class in Java, you will often want to override the `equals()` method in order to provide a more meaningful way to compare two objects of the same class. How this method is implemented is completely up to the developer's judgement.
For example, you may decide that two `Person`s should be considered "equal" if their `name` and `dateOfBirth` are the same. This logic would be implemented in your `Person` class's `equals()` method: For example, you may decide that two `Person` objects should be considered *equal* if their `name` and `dateOfBirth` instance variables are the same. This logic would be implemented in your `Person` class's `equals()` method:
```java ```java
public class Person { public class Person {
public String name; public String name;
public Date dateOfBirth; public Date dateOfBirth;
//The two lines above are instance attributes of the Person object
public boolean equals(Person person) { public boolean equals(Person person) {
return this.name.equals(person.name) && this.dateOfBirth.equals(person.dateOfBirth); return this.name.equals(person.name) && this.dateOfBirth.equals(person.dateOfBirth);
} //An edited equals() method can allow for the developer to choose what characteristics of an object should be compared in order to deem them equal
}
} }
``` ```