Assume a list:

List<String> items = Arrays.asList("apple", "banana", "apple", "orange", "banana", "apple");

Using Collectors.groupingBy + max()

String mostFrequent = items.stream()
    .collect(Collectors.groupingBy(Function.identity(), Collectors.counting()))
    .entrySet().stream()
    .max(Map.Entry.comparingByValue())
    .map(Map.Entry::getKey)
    .orElse(null); // returns null if list is empty

System.out.println(mostFrequent);

Output:

apple

Summary:

• Collectors.groupingBy(..., Collectors.counting()) counts occurrences of each element.
• .max(Map.Entry.comparingByValue()) finds the entry with the highest count.
• .map(Map.Entry::getKey) extracts the most frequent element.
• Returns null if the list is empty.