Can you explain what the load factor metric means in the HashMap data structure?

The load factor in HashMap is a coefficient that indicates how full the hash table is. It is calculated as the ratio of the number of elements in the map to the size of the bucket array (internal bins for storing elements).

For example, if the load factor is 0.75, it means that when 75% of the total buckets are filled, the HashMap will increase its size (rehash) to maintain the efficiency of search and insert operations.

A high load factor saves memory but increases the likelihood of collisions and slows down operations. A low load factor reduces collisions but requires more memory.

In Java, the default load factor is 0.75, which is considered a good balance between performance and memory usage.