Parser refactoring

ContentProvider.java

import java.io.*;
import java.util.concurrent.locks.ReentrantLock;

/**
 * This class allows to read/write content to provided file.
 * Class is thread-safe.
 */
public class ContentProvider {
    private File file;
    private ReentrantLock lock = new ReentrantLock();

    public ContentProvider(String fileName) {
        this.file = new File(fileName);
    }

    public String getContent() throws IOException {
        StringBuilder output = new StringBuilder();
        lock.lock();

        try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
            String line;
            while ((line = reader.readLine()) != null) {
                output.append(line);
                output.append(System.lineSeparator());
            }
        } finally {
            lock.unlock();
        }
        return output.toString();
    }

    public String getContentWithoutUnicode() throws IOException {
        StringBuilder output = new StringBuilder();
        lock.lock();

        try (FileInputStream input = new FileInputStream(file)) {
            int symbol;
            while ((symbol = input.read()) > 0) {
                if (symbol < 0x80) {
                    output.append((char) symbol);
                }
            }
        } finally {
            lock.unlock();
        }
        return output.toString();
    }

    public void saveContent(String content) throws IOException {
        lock.lock();
        try (BufferedWriter output = new BufferedWriter(new FileWriter(file))) {
            output.write(content);
        } finally {
            lock.unlock();
        }
    }
}