To implement a binary search in Java, you can follow these steps:

1. Sort the array: Binary search requires the array to be sorted in ascending order for efficient searching. You can use the Arrays.sort() method or any other sorting algorithm to sort the array.
2. Define the binary search method: Create a method that performs the binary search. This method should take the sorted array and the target value as parameters and return the index of the target value if found, or -1 if not found.
3. Implement the binary search algorithm: Inside the binary search method, use a loop to divide the search space in half until the target value is found or the search space is exhausted. Compare the target value with the middle element of the current search space and adjust the search space accordingly.