Question: In my application i want to replace space with %20 in my string.I tried in this way,

```
String flag1="http://74.208.194.142/admin/upload_image/1342594079_images (2).jpg";
flag1.replaceAll("", "%20");

```

But it is not working please help me.I am getting null pointer exception.

Answer: 
Have a look at <http://docs.oracle.com/javase/1.5.0/docs/api/java/net/URLEncoder.html>

It is not only the blanks that need to be replaced. URLs consist of special caracters for special meanings (e.g. the question mark to start the query string)

```
String flag1 = URLEncoder.encode("This string has spaces", "UTF-8")

```
```
    String flag1="http://74.208.194.142/admin/upload_image/1342594079_images (2).jpg";
    URI uri = null;
    try {
        uri = new URI(flag1.replaceAll(" ", "%20"));
    } catch (URISyntaxException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    System.out.println(uri);

```

The console will display output as 

`http://74.208.194.142/admin/upload_image/1342594079_images%20(2).jpg`