A persistent CookieStore implementation for use in Android with HTTPUrlConnection or OkHttp 2. -- For a OkHttp 3 persistent CookieJar implementation you can use this library: https://github.com/franmontiel/PersistentCookieJar

## PersistentCookieStore.java
/*
 * Copyright (c) 2015 Fran Montiel
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class PersistentCookieStore implements CookieStore {
    private static final String TAG = PersistentCookieStore.class
            .getSimpleName();

    // Persistence
    private static final String SP_COOKIE_STORE = "cookieStore";
    private static final String SP_KEY_DELIMITER = "|"; // Unusual char in URL
    private static final String SP_KEY_DELIMITER_REGEX = "\\"
            + SP_KEY_DELIMITER;
    private SharedPreferences sharedPreferences;

    // In memory
    private Map<URI, Set<HttpCookie>> allCookies;

    public PersistentCookieStore(Context context) {
        sharedPreferences = context.getSharedPreferences(SP_COOKIE_STORE,
                Context.MODE_PRIVATE);
        loadAllFromPersistence();
    }

    private void loadAllFromPersistence() {
        allCookies = new HashMap<URI, Set<HttpCookie>>();

        Map<String, ?> allPairs = sharedPreferences.getAll();
        for (Entry<String, ?> entry : allPairs.entrySet()) {
            String[] uriAndName = entry.getKey().split(SP_KEY_DELIMITER_REGEX,
                    2);
            try {
                URI uri = new URI(uriAndName[0]);
                String encodedCookie = (String) entry.getValue();
                HttpCookie cookie = new SerializableHttpCookie()
                        .decode(encodedCookie);

                Set<HttpCookie> targetCookies = allCookies.get(uri);
                if (targetCookies == null) {
                    targetCookies = new HashSet<HttpCookie>();
                    allCookies.put(uri, targetCookies);
                }
                // Repeated cookies cannot exist in persistence
                // targetCookies.remove(cookie)
                targetCookies.add(cookie);
            } catch (URISyntaxException e) {
                Log.w(TAG, e);
            }
        }
    }

    @Override
    public synchronized void add(URI uri, HttpCookie cookie) {
        uri = cookieUri(uri, cookie);

        Set<HttpCookie> targetCookies = allCookies.get(uri);
        if (targetCookies == null) {
            targetCookies = new HashSet<HttpCookie>();
            allCookies.put(uri, targetCookies);
        }
        targetCookies.remove(cookie);
        targetCookies.add(cookie);

        saveToPersistence(uri, cookie);
    }

    /**
     * Get the real URI from the cookie "domain" and "path" attributes, if they
     * are not set then uses the URI provided (coming from the response)
     *
     * @param uri
     * @param cookie
     * @return
     */
    private static URI cookieUri(URI uri, HttpCookie cookie) {
        URI cookieUri = uri;
        if (cookie.getDomain() != null) {
            // Remove the starting dot character of the domain, if exists (e.g: .domain.com -> domain.com)
            String domain = cookie.getDomain();
            if (domain.charAt(0) == '.') {
                domain = domain.substring(1);
            }
            try {
                cookieUri = new URI(uri.getScheme() == null ? "http"
                        : uri.getScheme(), domain,
                        cookie.getPath() == null ? "/" : cookie.getPath(), null);
            } catch (URISyntaxException e) {
                Log.w(TAG, e);
            }
        }
        return cookieUri;
    }

    private void saveToPersistence(URI uri, HttpCookie cookie) {
        SharedPreferences.Editor editor = sharedPreferences.edit();

        editor.putString(uri.toString() + SP_KEY_DELIMITER + cookie.getName(),
                new SerializableHttpCookie().encode(cookie));

        editor.apply();
    }

    @Override
    public synchronized List<HttpCookie> get(URI uri) {
        return getValidCookies(uri);
    }

    @Override
    public synchronized List<HttpCookie> getCookies() {
        List<HttpCookie> allValidCookies = new ArrayList<HttpCookie>();
        for (URI storedUri : allCookies.keySet()) {
            allValidCookies.addAll(getValidCookies(storedUri));
        }

        return allValidCookies;
    }

    private List<HttpCookie> getValidCookies(URI uri) {
        List<HttpCookie> targetCookies = new ArrayList<HttpCookie>();
        // If the stored URI does not have a path then it must match any URI in
        // the same domain
        for (URI storedUri : allCookies.keySet()) {
            // Check ith the domains match according to RFC 6265
            if (checkDomainsMatch(storedUri.getHost(), uri.getHost())) {
                // Check if the paths match according to RFC 6265
                if (checkPathsMatch(storedUri.getPath(), uri.getPath())) {
                    targetCookies.addAll(allCookies.get(storedUri));
                }
            }
        }

        // Check it there are expired cookies and remove them
        if (!targetCookies.isEmpty()) {
            List<HttpCookie> cookiesToRemoveFromPersistence = new ArrayList<HttpCookie>();
            for (Iterator<HttpCookie> it = targetCookies.iterator(); it
                    .hasNext(); ) {
                HttpCookie currentCookie = it.next();
                if (currentCookie.hasExpired()) {
                    cookiesToRemoveFromPersistence.add(currentCookie);
                    it.remove();
                }
            }

            if (!cookiesToRemoveFromPersistence.isEmpty()) {
                removeFromPersistence(uri, cookiesToRemoveFromPersistence);
            }
        }
        return targetCookies;
    }

   /* http://tools.ietf.org/html/rfc6265#section-5.1.3

    A string domain-matches a given domain string if at least one of the
    following conditions hold:

    o  The domain string and the string are identical.  (Note that both
    the domain string and the string will have been canonicalized to
    lower case at this point.)

    o  All of the following conditions hold:

        *  The domain string is a suffix of the string.

        *  The last character of the string that is not included in the
           domain string is a %x2E (".") character.

        *  The string is a host name (i.e., not an IP address). */

    private boolean checkDomainsMatch(String cookieHost, String requestHost) {
        return requestHost.equals(cookieHost) || requestHost.endsWith("." + cookieHost);
    }

    /*  http://tools.ietf.org/html/rfc6265#section-5.1.4

        A request-path path-matches a given cookie-path if at least one of
        the following conditions holds:

        o  The cookie-path and the request-path are identical.

        o  The cookie-path is a prefix of the request-path, and the last
        character of the cookie-path is %x2F ("/").

        o  The cookie-path is a prefix of the request-path, and the first
        character of the request-path that is not included in the cookie-
        path is a %x2F ("/") character. */

    private boolean checkPathsMatch(String cookiePath, String requestPath) {
        return requestPath.equals(cookiePath) ||
                (requestPath.startsWith(cookiePath) && cookiePath.charAt(cookiePath.length() - 1) == '/') ||
                (requestPath.startsWith(cookiePath) && requestPath.substring(cookiePath.length()).charAt(0) == '/');
    }

    private void removeFromPersistence(URI uri, List<HttpCookie> cookiesToRemove) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        for (HttpCookie cookieToRemove : cookiesToRemove) {
            editor.remove(uri.toString() + SP_KEY_DELIMITER
                    + cookieToRemove.getName());
        }
        editor.apply();
    }

    @Override
    public synchronized List<URI> getURIs() {
        return new ArrayList<URI>(allCookies.keySet());
    }

    @Override
    public synchronized boolean remove(URI uri, HttpCookie cookie) {
        Set<HttpCookie> targetCookies = allCookies.get(uri);
        boolean cookieRemoved = targetCookies != null && targetCookies
                .remove(cookie);
        if (cookieRemoved) {
            removeFromPersistence(uri, cookie);
        }
        return cookieRemoved;

    }

    private void removeFromPersistence(URI uri, HttpCookie cookieToRemove) {
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.remove(uri.toString() + SP_KEY_DELIMITER
                + cookieToRemove.getName());
        editor.apply();
    }

    @Override
    public synchronized boolean removeAll() {
        allCookies.clear();
        removeAllFromPersistence();
        return true;
    }

    private void removeAllFromPersistence() {
        sharedPreferences.edit().clear().apply();
    }

}

## SerializableHttpCookie.java
/*
 * Copyright (c) 2011 James Smith <james@loopj.com>
 * Copyright (c) 2015 Fran Montiel
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Based on the code from this stackoverflow answer http://stackoverflow.com/a/25462286/980387 by janoliver
 * Modifications in the structure of the class and addition of serialization of httpOnly attribute
 */

public class SerializableHttpCookie implements Serializable {
    private static final String TAG = SerializableHttpCookie.class
            .getSimpleName();

    private static final long serialVersionUID = 6374381323722046732L;

    private transient HttpCookie cookie;

    // Workaround httpOnly: The httpOnly attribute is not accessible so when we
    // serialize and deserialize the cookie it not preserve the same value. We
    // need to access it using reflection
    private Field fieldHttpOnly;

    public SerializableHttpCookie() {
    }

    public String encode(HttpCookie cookie) {
        this.cookie = cookie;

        ByteArrayOutputStream os = new ByteArrayOutputStream();
        try {
            ObjectOutputStream outputStream = new ObjectOutputStream(os);
            outputStream.writeObject(this);
        } catch (IOException e) {
            Log.d(TAG, "IOException in encodeCookie", e);
            return null;
        }

        return byteArrayToHexString(os.toByteArray());
    }

    public HttpCookie decode(String encodedCookie) {
        byte[] bytes = hexStringToByteArray(encodedCookie);
        ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(
                bytes);
        HttpCookie cookie = null;
        try {
            ObjectInputStream objectInputStream = new ObjectInputStream(
                    byteArrayInputStream);
            cookie = ((SerializableHttpCookie) objectInputStream.readObject()).cookie;
        } catch (IOException e) {
            Log.d(TAG, "IOException in decodeCookie", e);
        } catch (ClassNotFoundException e) {
            Log.d(TAG, "ClassNotFoundException in decodeCookie", e);
        }

        return cookie;
    }

    // Workaround httpOnly (getter)
    private boolean getHttpOnly() {
        try {
            initFieldHttpOnly();
            return (boolean) fieldHttpOnly.get(cookie);
        } catch (Exception e) {
            // NoSuchFieldException || IllegalAccessException ||
            // IllegalArgumentException
            Log.w(TAG, e);
        }
        return false;
    }

    // Workaround httpOnly (setter)
    private void setHttpOnly(boolean httpOnly) {
        try {
            initFieldHttpOnly();
            fieldHttpOnly.set(cookie, httpOnly);
        } catch (Exception e) {
            // NoSuchFieldException || IllegalAccessException ||
            // IllegalArgumentException
            Log.w(TAG, e);
        }
    }

    private void initFieldHttpOnly() throws NoSuchFieldException {
        fieldHttpOnly = cookie.getClass().getDeclaredField("httpOnly");
        fieldHttpOnly.setAccessible(true);
    }

    private void writeObject(ObjectOutputStream out) throws IOException {
        out.writeObject(cookie.getName());
        out.writeObject(cookie.getValue());
        out.writeObject(cookie.getComment());
        out.writeObject(cookie.getCommentURL());
        out.writeObject(cookie.getDomain());
        out.writeLong(cookie.getMaxAge());
        out.writeObject(cookie.getPath());
        out.writeObject(cookie.getPortlist());
        out.writeInt(cookie.getVersion());
        out.writeBoolean(cookie.getSecure());
        out.writeBoolean(cookie.getDiscard());
        out.writeBoolean(getHttpOnly());
    }

    private void readObject(ObjectInputStream in) throws IOException,
            ClassNotFoundException {
        String name = (String) in.readObject();
        String value = (String) in.readObject();
        cookie = new HttpCookie(name, value);
        cookie.setComment((String) in.readObject());
        cookie.setCommentURL((String) in.readObject());
        cookie.setDomain((String) in.readObject());
        cookie.setMaxAge(in.readLong());
        cookie.setPath((String) in.readObject());
        cookie.setPortlist((String) in.readObject());
        cookie.setVersion(in.readInt());
        cookie.setSecure(in.readBoolean());
        cookie.setDiscard(in.readBoolean());
        setHttpOnly(in.readBoolean());
    }

    /**
     * Using some super basic byte array &lt;-&gt; hex conversions so we don't
     * have to rely on any large Base64 libraries. Can be overridden if you
     * like!
     *
     * @param bytes byte array to be converted
     * @return string containing hex values
     */
    private String byteArrayToHexString(byte[] bytes) {
        StringBuilder sb = new StringBuilder(bytes.length * 2);
        for (byte element : bytes) {
            int v = element & 0xff;
            if (v < 16) {
                sb.append('0');
            }
            sb.append(Integer.toHexString(v));
        }
        return sb.toString();
    }

    /**
     * Converts hex values from strings to byte array
     *
     * @param hexString string of hex-encoded values
     * @return decoded byte array
     */
    private byte[] hexStringToByteArray(String hexString) {
        int len = hexString.length();
        byte[] data = new byte[len / 2];
        for (int i = 0; i < len; i += 2) {
            data[i / 2] = (byte) ((Character.digit(hexString.charAt(i), 16) << 4) + Character
                    .digit(hexString.charAt(i + 1), 16));
        }
        return data;
    }
}