The role of equals in java

The equals() method in Java is used to compare the equality of two objects and check their internal status, including: Value equality: whether the values ​​of the two objects are the same. Reference equality: whether two objects refer to the same object. Object type equality: Whether two objects have the same type, ignoring values ​​and references.

The role of equals() method in Java

In Java, equals() Method used to compare two objects for equality. It is a method used to determine whether two objects represent the same entity.

Detailed explanation of its function

equals() method checks the internal state of two objects to determine whether they are equal. It typically implements the following behavior:

• Value equality: Two objects are considered equal if their values ​​are the same. For example, two integer objects are equal if they have the same value.
• Reference equality: Two objects are considered equal if they refer to the same object. For example, two string objects are equal if they point to the same memory location.
• Object type equality: Two objects can have different values ​​and refer to different objects and still be equal, as long as they have the same type. This is typically used to compare instances of custom classes.

Usage

To compare two objects for equality, you can use equals() The method is as follows:

if (object1.equals(object2)) {
    // 两个对象相等
} else {
    // 两个对象不相等
}

Importance

##equals() method is crucial for Java applications as it is used to determine the equality of objects in various scenarios , including:

Comparison of objects in collections
• Comparison of keys in Map
• Compare the status of GUI components
• Compare database records

Note

For basic types (such as int, double, etc.), the
• equals() method compares values. rather than a quote.
For reference types (such as objects), the
• equals() method compares references unless the class explicitly overrides this method.
When overriding the
• equals() method, you should also override the hashCode() method to ensure that objects have the same hash value in the collection.

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