What is the difference between Java linked lists and arrays?

The main differences between Java linked lists and arrays are as follows:

1. Data structures: Arrays are a type of linear data structure where elements are stored in continuous memory space and can be accessed and modified using indices. Linked lists are a type of data structure where elements are stored in non-contiguous memory space and each element contains a pointer to the next element.
2. Variability in size: Arrays have a fixed size that is determined at the time of creation and cannot be changed dynamically. On the other hand, linked lists have a flexible size that can be adjusted as needed by inserting or deleting elements.
3. Efficiency of insertions and deletions: Arrays require moving other elements to maintain continuity when inserting or deleting elements, with an average time complexity of O(n). On the other hand, linked lists only need to modify node pointers when inserting or deleting elements, with a time complexity of O(1).
4. Efficiency of random access: Arrays can access elements directly by index with a time complexity of O(1), while linked lists require traversal from the head node to find the specified position, resulting in a time complexity of O(n).
5. Space Utilization: Arrays in memory require a contiguous block of space, and if the space is insufficient, a larger space needs to be reallocated and elements copied. On the other hand, the space for a linked list can be discrete, only needing to allocate space for new nodes.

In conclusion, arrays are suitable for scenarios requiring random access to elements and a fixed size, while linked lists are suitable for scenarios requiring frequent insertion and deletion of elements with an uncertain size.