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HashMap Operations and Iteration

Demonstrates HashMap operations including put, get, merge, computeIfAbsent, and iteration with entrySet, keySet, and forEach methods.

JavaData Integrity

Code

snippet
import java.util.*;
import java.util.function.*;

public class HashMapOperations {

    public static void main(String[] args) {
        Map<String, Integer> wordCount = new HashMap<>();

        String[] words = "the quick brown fox jumps the lazy dog the fox".split(" ");

        for (String word : words) {
            wordCount.merge(word, 1, Integer::sum);
        }
        System.out.println("Word counts: " + wordCount);

        Map<String, List<String>> grouped = new HashMap<>();
        String[] items = {"apple:fruit", "carrot:veg", "banana:fruit", "celery:veg"};

        for (String item : items) {
            String[] parts = item.split(":");
            grouped.computeIfAbsent(parts[1], k -> new ArrayList<>())
                   .add(parts[0]);
        }
        System.out.println("Grouped: " + grouped);

        wordCount.forEach((word, count) -> {
            if (count > 1) {
                System.out.println("Repeated: " + word + " (" + count + ")");
            }
        });

        int total = wordCount.values().stream()
            .mapToInt(Integer::intValue)
            .sum();
        System.out.println("Total words: " + total);

        Map<String, Integer> sorted = new TreeMap<>(wordCount);
        System.out.println("Sorted keys: " + sorted.keySet());
    }
}

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