How is the hashCode of an object generated by default in Java?

By default, the hashCode() method in Java is implemented in the Object class and returns an integer value, which is usually based on the internal memory address of the object (although the specification does not guarantee this).

This means that for different objects, even with the same fields, hashCode() will return different values if the method is not overridden.

If a class does not override hashCode(), then:

• Calling hashCode() on an object returns a value related to its identity.
• This value remains constant throughout the life of the object.

For proper operation in collections such as HashMap or HashSet, it is important to override hashCode() along with equals(), so that objects with the same field values have the same hash code.

Example of default behavior:

Object obj = new Object();
System.out.println(obj.hashCode()); // For example, 12345678

Object obj2 = new Object();
System.out.println(obj2.hashCode()); // Another number, for example, 87654321

Thus, by default, hashCode() is a unique identifier of the object based on its address in memory.