When to use hashCode?

So, the question is, "When exactly should we be using hashCode in our programming endeavors, especially in the realm of cryptocurrency and finance?" Is it a necessary component for every class we create? Does it play a pivotal role in ensuring the integrity and efficiency of our data structures, especially when dealing with large sets of blockchain transactions or financial records? And if so, how does it contribute to the overall performance and scalability of our systems? Let's delve deeper into the intricacies of hashCode and uncover its true significance in the world of cryptocurrency and finance.