In Java, there are several built-in data structures that you can use to store and organize data in your programs. Some common data structures in Java include:

• Arrays: An array is a fixed-size collection of elements of the same type. You can access the elements of an array using an index.

• ArrayLists: An ArrayList is a resizable array that allows you to add and remove elements dynamically. It is a part of the Java Collection Framework.

• LinkedLists: A LinkedList is a linear data structure in which each element is a separate object linked to the previous and next elements. It is also a part of the Java Collection Framework.

• HashMaps: A HashMap is a map implementation that uses a hash table to store key-value pairs. It allows you to look up values based on a key and is useful for storing data that needs to be quickly retrieved.

• Trees: A tree is a data structure that consists of nodes organized into a hierarchy. Each node in a tree has a value and can have zero or more children. There are several types of trees, including binary trees and balanced trees.

• Stacks: A stack is a linear data structure that allows you to push and pop elements in a last-in, first-out (LIFO) order.

• Queues: A queue is a linear data structure that allows you to add and remove elements in a first-in, first-out (FIFO) order.

You can use these data structures to store and organize data in your Java programs, depending on your specific needs. For example, you might use an ArrayList to store a list of items that needs to be dynamically resized, or a HashMap to store key-value pairs that need to be quickly retrieved.