Why Does Java's `Object.toString()` Include the Hash Code?

The Inclusion of the Hash Code in Object.toString()

The Object.toString() method provides a string representation of an object. By default, this string includes the object's class name followed by an @ symbol and the object's hash code. For instance, the output of System.out.println(someObj.toString()) might resemble someObjectClassname@hashcodenumber.

The Rationale Behind Hash Code Inclusion

The hash code is a unique identifier for an object in Java. While not guaranteed to be unique, identical objects typically have the same hash code. The default toString() implementation incorporates the hash code to facilitate the distinction between different object instances.

Its inclusion also serves a practical purpose in error messages, allowing developers to quickly identify the offending object. By providing both the class name and hash code, the error message offers helpful context for troubleshooting.

It's worth noting that the specific format of the string representation may vary depending on the object's class. However, the inclusion of the hash code remains a common practice for providing a concise and informative string representation of objects in Java.

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