TextSummarizer.java

import java.util.*;

public class TextSummarizer {

    public static String summarize(String text, int numSentences) {
        // Sentence splitting
        String[] sentences = text.split("(?<=[.!?])\\s+");

        // Word frequency map
        Map<String, Integer> wordFreq = new HashMap<>();
        for (String sentence : sentences) {
            for (String word : sentence.toLowerCase().replaceAll("[^a-zA-Z ]", "").split("\\s+")) {
                if (!word.isEmpty()) {
                    wordFreq.put(word, wordFreq.getOrDefault(word, 0) + 1);
                }
            }
        }

        // Score each sentence
        Map<String, Integer> sentenceScores = new HashMap<>();
        for (String sentence : sentences) {
            int score = 0;
            for (String word : sentence.toLowerCase().replaceAll("[^a-zA-Z ]", "").split("\\s+")) {
                score += wordFreq.getOrDefault(word, 0);
            }
            sentenceScores.put(sentence, score);
        }

        // Sort and pick top sentences
        List<Map.Entry<String, Integer>> sorted = new ArrayList<>(sentenceScores.entrySet());
        sorted.sort((a, b) -> b.getValue() - a.getValue());

        StringBuilder summary = new StringBuilder();
        for (int i = 0; i < Math.min(numSentences, sorted.size()); i++) {
            summary.append(sorted.get(i).getKey()).append(" ");
        }

        return summary.toString().trim();
    }

    public static void main(String[] args) {
        String text = "Machine learning is the study of computer algorithms that improve automatically through experience. It is seen as a part of artificial intelligence. Machine learning algorithms build a model based on sample data, known as training data. The field of machine learning is closely related to computational statistics.";
        
        String summary = summarize(text, 2);
        System.out.println("Summary:\n" + summary);
    }
}