About trim() for String

Question

I am doing assignment to deal with the xml code,for every line I read by BufferedReader I have to trim() it,I mean to take away all the white space in this line before I do something with the xml code.but I cannot make it right.the "trim()" seems doesn't work.
so I write some small code to test it,
while(in.ready())
String line = in.readLine();
line.trim();
System.out.println();
but,unfortunately,I found the "trim()" mothod in String does't work,it does't do anything!
because on the screen,it print out the excatly same thing as these code
while(in.ready())
String line = in.readLine();
System.out.println();
it did't take away the white sapce.
can you help me?thank you very much!

Answer 1

here is my xml code:
<database>
     <product>
          <id>No.1</id>
          <name>skateboard</name>
          <type>sports</type>
          <price>$58</price>
     </product>
     <product>
          <id>No.2</id>
          <name>bicycle</name>
          <type>sports</type>
          <price>$122</price>
     </product>
</database>
i suppose to have it print out like:
<database>
<product>
<id>No.1</id>
<name>skateboard</name>
<type>sports</type>
<price>$58</price>
</product>
<product>
<id>No.2</id>
<name>bicycle</name>
<type>sports</type>
<price>$122</price>
/product>
</database>