StringListSerialize.java

import java.util.ArrayList;
import java.util.List;

public class StringListSerialize {

    public static final String DELIMITER = ",";

    public static String serialize(List<String> strings) {
        StringBuilder metadata = new StringBuilder();
        StringBuilder concat = new StringBuilder();
        for (String s: strings) {
            metadata.append(s.length());
            metadata.append(DELIMITER);
            concat.append(s);
        }
        return metadata.length() + DELIMITER + metadata.toString() + concat.toString();
    }

    public static List<String> deserialize(String serializedList) {
        // The List we'll return
        List<String> result = new ArrayList<String>();

        int lengthIndex = serializedList.indexOf(DELIMITER);
        int metadataLength = Integer.parseInt(serializedList.substring(0, lengthIndex));
            
        // The index at which to start reading data
        int currentIndex = lengthIndex + 1 + metadataLength;
        String[] metadata = serializedList.substring(lengthIndex + 1, lengthIndex + 1 + metadataLength).split(DELIMITER);

        for(String strLength: metadata) {
            int length = Integer.parseInt(strLength);
            result.add(serializedList.substring(currentIndex, currentIndex+length));
            currentIndex = currentIndex + length;
        }

        return result;
    }

    public static void main(String[] args) {
        List<String> strings = new ArrayList<String>();
        strings.add("This");
        strings.add("Is");
        strings.add("A");
        strings.add("Test");
        strings.add("Collection");

        String ser = serialize(strings);
        System.out.println(ser);
        for (String s : deserialize(ser)) {
            System.out.println(s);
        }
    }
}