try {
    URL url = new URL("http://169.254.169.254/latest");

    URLConnection connection = url.openConnection();
    connection.setConnectTimeout(5000);
    connection.connect();
    System.out.println("Connected successfully using url");
} catch (IOException e) {
        e.printStackTrace();
}

I expected the behavior is: connect should be success if the host is reachable, else throw exception. It works fine without the anti-virus application, but always print “connected successfully” even the host is not reachable.

Then I tried to use Socket to connect:

Socket socket = new Socket();
socket.connect(new InetSocketAddress("169.254.169.254", 80));
if (socket.isConnected()) {
    System.out.println("Connected successfully using socket");
} else {
    System.out.println("Connected failed using socket");
}

But Still got the same problem.

The solution for it:

Disable http check in anti-virus, for example, in ESET NOD32, the settings is Web access protection -> Http, Https -> Http scanner

After customized the toolbar, the buttons enabled, and it’s very easy to add comments, but the menu item still disabled.

The following is what I found about how to customize the toolbar from the Preview Help.

Adding text to an image

You can add text to an image to describe what’s in it or when the image was created.

After you save the image, you can’t edit, move, or delete any text you added to it. If you think you’ll need to edit the text, convert the image to a PDF document, and then add notes to the PDF document. Notes added to a PDF document can be edited after they’re saved.

To add text to an image:

1. If the Annotate pop-up menu isn’t in the toolbar, choose View > Customize Toolbar and drag the Annotate pop-up menu to the toolbar.
2. Choose Note from the Annotate pop-up menu in the toolbar.
3. Drag over the area where you want the text to appear.
4. Enter your text.

Before you save the image, you can move, resize, edit, or delete the text. First choose Text Annotation from the Annotation pop-up menu in the toolbar. Then to edit the text, double-click it. To delete the text, click it so resize handles appear, and then press Delete.

purpose:
generate sql like:   

select * from photo p
    left join artist a on p.artist_id = a.artist_id
      where a.genre = 'something' and p.genre = 'something'

code:           

if(!CriteriaUtil::hasJoin($criteria, ArtistPeer::TABLE_NAME)){
    $criteria->addJoin(PhotoPeer::ARTIST_ID, ArtistPeer::ARTIST_ID, Criteria::LEFT_JOIN);
}
$criteria->add(ArtistPeer::GENRE, $genre);    
$criteria->add(PhotoPeer::GENRE, $genre);

2. join two tables, add AND OR between conditions
purpose:
generate sql like:    

select * from photo p
    left join artist a on p.artist_id = a.artist_id
      where (a.genre = 'some' or p.genre='something')
        and a.name = 'something'

code:   

if(!CriteriaUtil::hasJoin($criteria, ArtistPeer::TABLE_NAME)){
   $criteria->addJoin(PhotoPeer::ARTIST_ID, ArtistPeer::ARTIST_ID, Criteria::LEFT_JOIN);
}
$criteria->add(ArtistPeer::GENRE, $genre);
$c = $criteria->getCriterion(ArtistPeer::GENRE);
if($c != null){
   $c->addOr($criteria->getNewCriterion(PhotoPeer::GENRE, $genre));
}
$criteria->add(ArtistPeer::NAME, $name);

Note:
It's a good habit to check if we have joined the table already. to check this, you can use the following util class, it get all the joined tables, and check if the table exists in them.

class CriteriaUtil{
    public static function hasJoin($c, $table_name){
        $joins = $c->getJoins();
        if($joins != null){
            foreach($joins as $join){
                if($join->getRightTableName() == $table_name){
                    return true;
                }
                if($join->getLeftTableName() == $table_name){
                    return true;
                }
            }
        }
        return false;
    }
}

After search on google, I found the resolution is import some settings into registry.

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{00020404-0000-0000-C000-000000000046}]
@="IEnumVARIANT"

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{00020404-0000-0000-C000-000000000046}\NumMethods]
@="7"

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{00020404-0000-0000-C000-000000000046}\ProxyStubClsid]
@="{00020421-0000-0000-C000-000000000046}"

[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Interface\{00020404-0000-0000-C000-000000000046}\ProxyStubClsid32]
@="{00020421-0000-0000-C000-000000000046}"

You can also download the file here, unzip and import it to your registry.

Clearing Selective Parts of the Cache

During application development, you have to clear the cache in various situations:

• When you create a new class: Adding a class to an autoloading directory (one of the project's lib/ folders) is not enough to have symfony find it automatically. You must clear the autoloading configuration cache so that symfony browses again all the directories of the autoload.yml file and references the location of autoloadable classes--including the new ones.
• When you change the configuration in production: The configuration is parsed only during the first request in production. Further requests use the cached version instead. So a change in the configuration in the production environment (or any environment where SF_DEBUG is turned off) doesn't take effect until you clear the cached version of the file.
• When you modify a template in an environment where the template cache is enabled: The valid cached templates are always used instead of existing templates in production, so a template change is ignored until the template cache is cleared or outdated.
• When you update an application with the sync command: This case usually covers the three previous modifications.

The problem with clearing the whole cache is that the next request will take quite long to process, because the configuration cache needs to be regenerated. Besides, the templates that were not modified will be cleared from the cache as well, losing the benefit of previous requests.

That means it's a good idea to clear only the cache files that really need to be regenerated. Use the options of the clear-cache task to define a subset of cache files to clear, as demonstrated in Listing 18-14.

Listing 18-14 - Clearing Only Selective Parts of the Cache

// Clear only the cache of the myapp application

> symfony clear-cache myapp



// Clear only the HTML cache of the myapp application

> symfony clear-cache myapp template



// Clear only the configuration cache of the myapp application

> symfony clear-cache myapp config

You can also remove files by hand in the cache/ directory, or clear template cache files selectively from the action with the $cacheManager->remove() method, as described inChapter 12

Note:

1. We can use $cacheManager->remove() to clear cache after we deployed a new version product.

2. write code to generate models from database, and then call $cacheManager->remove() to clear cache.

#get the first parameter as the database name
DATABASE=$1
#if no database specified, then you can set the default one
if [ -z $DATABASE ]; then

DATABASE=default_database_name_here

fi



#mysql user and password to backup the database.
MYSQLUSER=mysql_user
MYSQLPWD=mysql_password
#path to backup
ARCHIVEPATH=~/backup/db_backup
DATE=`date +%Y%m%d`
YEAR=`date +%Y`
MONTH=`date +%m`
FOLDER_MONTH=$ARCHIVEPATH/$YEAR$MONTH
if [ ! -d $FOLDER_MONTH ]; then

echo "mkdir $FOLDER_MONTH"
mkdir $FOLDER_MONTH
fi
# Backup
echo "mysqldump -u$MYSQLUSER -p$MYSQLPWD $DATABASE | gzip > $FOLDER_MONTH/$DATABASE-$DATE.sql.gz"
mysqldump -u$MYSQLUSER -p$MYSQLPWD $DATABASE | gzip > $FOLDER_MONTH/$DATABASE-$DATE.sql.gz

and you can add the script to cron job under *nix and schedule under windows:

*nix:

Save the following text in file: db_backup.at

10 * * * * ~/backup/backup_db.sh databasename

and call

crontab db_backup.at

You need to change the period to run the script for your business, e.g. each day, each week etc.

#server-id       = 1
log-bin         = /var/log/mysql/mysql-bin.log
#if you set the expire_logs_days = x var in the [mysqld] section of your my.cnf it will automatically rotate your bin logs after x days.
expire_logs_days = 30
#it will create a new log file when the current file reach the specified size.
max_binlog_size = 100M