To enable JBoss http protocol gzip compression you have to change the server.xml file.
Location:
Less than 4.0 Version : ${jBoss-home}\server\default\deploy\jbossweb-tomcat50.sar\server.xml
above 4.0 Version     : ${jBoss-home}\server\default\deploy\jboss-web.deployer\server.xml

Find this piece of xml code:
<Connector port=”8080″ address=”${jboss.bind.address}” maxThreads=”250″
maxHttpHeaderSize=”8192″ emptySessionPath=”true” protocol=”HTTP/1.1″
enableLookups=”false” redirectPort=”8443″ acceptCount=”100″ connectionTimeout=”20000″
disableUploadTimeout=”true” compression=”0″></Connector>

When compression is disabled compression parameter is set to 0.
To enable compression set it to 1.

After that you can see the difference.
It can compress HTML,CSS,JavaScript,Images File from 1 MB to around 300kb.

Popularity: 5% [?]

Generics:

Generics provides compile-time (static) type safety for collections and
eliminates the need for most typecasts (type conversion).

For Example:

List<String> stringList = new ArrayList<String>();
stringList.add(“one”);
stringList.add(“two”);
stringList.add(“three”);
stringList.add(“four”);
stringList.add(“five”);

In the above example,we can add only the String in a ArrayList.If we add
Other than String mean it’s throw an error.

Other Uses Of Generics are:
In For loop we directly use without checking condition of length.

Example:
Previously Used For Loop:
========================
String value=”";
for(int i=0;i<stringList.length();i++)
{
value=(String)stringList.get(i);
System.out.println(value);
}

Generic For Loop
================
for(String value : stringList)
{
System.out.println(value);
}

Popularity: 2% [?]

String
=====
String are immutable object.Its value cannot be changed(constant).String object are readonly.If you create one instance of string and change the value of string then it create new instance.

String Buffer
=========
String Buffer is mutable.Its Value can be Changed.If you create one instance and append the text without creating a new instance

Example:
======
String
=====
String str=”welcome”;
str + = “to fordevs”;

String Buffer
=========
StringBuffer strbuff=new StringBuffer(“welcome”);
strbuff.append(“to fordevs”);

Both code give same output but Second approach much faster than first one.

Popularity: 6% [?]