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The equals method in Java is used to compare two objects for equality. It compares the fields of two objects one by one and checks whether they are equal to determine object content equality. When overriding the equals method, you should adhere to the symmetry, reflexivity, transitivity, and consistency conventions.
equals usage in Java
In Java, the equals
method is used Compares two objects for equality. It is a generic method defined by the Object
class and inherited by all other classes.
Usage
equals
method is usually used to compare the value content of two objects, rather than the reference Equality. It takes another object as a parameter and returns a boolean
value indicating whether the two objects are equal.
Syntax:
<code class="java">public boolean equals(Object obj)</code>
Parameters
- The object to be compared
Return value
- if two objects are equal
- if two objects Not equal
Detailed explanation
When comparing two objects, theequals method performs the following steps:
method checks whether two objects are instances of the same type. The objects are definitely not equal if they do not belong to the same class.
method will compare the fields or properties of the two objects. It will compare the corresponding fields one by one and check if they are equal.
method may compare objects for reference equality. This means it checks if two objects point to the same memory location. They are considered equal if they point to the same memory location.
Notes
equals method, be sure to adhere to the following conventions:
and
y,
x.equals(y) is equal to
y.equals(x).
,
x.equals(x) must be
true.
,
y and
z, if
x.equals(y ) is
true and
y.equals(z) is
true, then
x.equals(z) must also be
true.
and
y, if they have not been modified, then
x is called multiple times. equals(y) must always return the same result.
methods defined for basic types (such as
int,
double) are final and cannot be overridden .
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