Remove the use of FileInputStream.available()

import android.os.FileUtils;

import android.os.Process;

import org.apache.harmony.luni.util.InputStreamHelper;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileOutputStream;

        return keyFile;

    }

    public String retrieveKeyHexString(String keyName) {

    public String retrieveKeyHexString(String keyName) throws IOException {

        return toHexString(retrieveKey(keyName));

    }

    public byte[] retrieveKey(String keyName) {

    public byte[] retrieveKey(String keyName) throws IOException {

        File keyFile = getKeyFile(keyName);

        if (!keyFile.exists()) {

            return null;

        }

        try {

        FileInputStream fis = new FileInputStream(keyFile);

            int keyLen = fis.available();

            byte[] retKey = new byte[keyLen];

            fis.read(retKey);

            fis.close();

            return retKey;

        } catch (IOException ioe) { }

        throw new IllegalArgumentException();

        return InputStreamHelper.readFullyAndClose(fis);

    }

    public void deleteKey(String keyName) {

        } catch (NoSuchAlgorithmException nsae) {

            Slog.e(TAG, "Failed to create encryption keys with exception: " + nsae);

            return null;

        } catch (IOException ioe) {

            Slog.e(TAG, "Failed to retrieve encryption keys with exception: "

                      + ioe);

            return null;

        }

    }

    /* package */ static String getTempContainerId() {