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")

```
In `flag1.replaceAll()`, your space is missing. try:

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

```

and set the result to the flag1.