I've do this code on DatabaseHelper.java

Line Number 34

public DatabaseHelper(Context context) throws IOException {
    super(context, DB_NAME, null, 1);
    this.mycontext = context;
    boolean dbexist = checkdatabase();
    if (dbexist) {
        // System.out.println("Database exists");
        opendatabase();
    } else {
        // System.out.println("Database doesn't exist");
        createdatabase();
    }
}

Line number 64

private boolean checkdatabase() {
    // SQLiteDatabase checkdb = null;
    boolean checkdb = false;
    try {
        String myPath = DB_PATH + DB_NAME;
        File dbfile = new File(myPath);
        checkdb = SQLiteDatabase.openDatabase(myPath, null,
                SQLiteDatabase.OPEN_READWRITE) != null;
        checkdb = dbfile.exists();
    } catch (SQLiteException e) {
        System.out.println("Database doesn't exist");
    }

    return checkdb;
}

Line number 44

On create method menu.java

try {
        db = new DatabaseHelper(this);
    } catch (IOException e2) {

        e2.printStackTrace();
    }

    try {
        db.createdatabase();
    } catch (IOException e) {

        e.printStackTrace();
    }
     db.getReadableDatabase();

    db.opendatabase();
    Random rand = new Random();
    randomJokId = rand.nextInt(603 - 1) + 1;
    cur = db.jokOfTheDay(randomJokId);
    cur.moveToFirst();
    String fullJok = cur.getString(cur.getColumnIndex("body"));
    String Jok = "";
    Jok = fullJok.substring(0, 55);
    jok_of_the_day.setText(Jok + "...  Read more");

    Log.d(TAG, "" + randomJokId);
}

Getting this error message

Another essential things, I've this error message happens three time.

01-19 13:49:41.284: ERROR/Database(10932): close() was never explicitly called on database '/data/data/com.horror.android/databases/jokesdatabase.sql' 
01-19 13:49:41.284: ERROR/Database(10932): android.database.sqlite.DatabaseObjectNotClosedException: Application did not close the cursor or database object that was opened here
01-19 13:49:41.284: ERROR/Database(10932):     at android.database.sqlite.SQLiteDatabase.<init>(SQLiteDatabase.java:1847)
01-19 13:49:41.284: ERROR/Database(10932):     at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:820)
01-19 13:49:41.284: ERROR/Database(10932):     at com.horror.android.DatabaseHelper.checkdatabase(DatabaseHelper.java:64)
01-19 13:49:41.284: ERROR/Database(10932):     at com.horror.android.DatabaseHelper.createdatabase(DatabaseHelper.java:45)
01-19 13:49:41.284: ERROR/Database(10932):     at com.horror.android.UltimateJokesMenu.onCreate(UltimateJokesMenu.java:51)
01-19 13:49:41.284: ERROR/Database(10932):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
01-19 13:49:41.284: ERROR/Database(10932):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
01-19 13:49:41.284: ERROR/Database(10932):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
01-19 13:49:41.284: ERROR/Database(10932):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
01-19 13:49:41.284: ERROR/Database(10932):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
01-19 13:49:41.284: ERROR/Database(10932):     at android.os.Handler.dispatchMessage(Handler.java:99)
01-19 13:49:41.284: ERROR/Database(10932):     at android.os.Looper.loop(Looper.java:130)
01-19 13:49:41.284: ERROR/Database(10932):     at android.app.ActivityThread.main(ActivityThread.java:3683)
01-19 13:49:41.284: ERROR/Database(10932):     at java.lang.reflect.Method.invokeNative(Native Method)
01-19 13:49:41.284: ERROR/Database(10932):     at java.lang.reflect.Method.invoke(Method.java:507)
01-19 13:49:41.284: ERROR/Database(10932):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
01-19 13:49:41.284: ERROR/Database(10932):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
01-19 13:49:41.284: ERROR/Database(10932):     at dalvik.system.NativeStart.main(Native Method)

Try calling SQLiteDatabase.close() in the finish of the try within the checkDatabase method.

use db.close(); to shut your Database and cur.close(); to shut your cursor once you finish dealing with them.