Why do we need public static void main(String args[]) method in Java

We need
• public: The method can be accessed outside the class / package
• static: You need not have an instance of the class to access the method
• void: Your application need not return a value, as the JVM launcher would return the value when it exits
• main(): This is the entry point for the application

If the main() was not static, you would require an instance of the class in order to execute the method.If this is the case, what would create the instance of the class? What if your class did not have a public constructor?

Self Study

The following is a link from w3 schools for .NET framework
I would want you to go through this tutorial

http://w3schools.com/ngws/default.asp

Dynamic Host Configuration Protocol (DHCP)

Dynamic Host Configuration Protocol (DHCP) is a protocol used by networked devices (clients) to obtain the parameters necessary for operation in an Internet Protocol network. This protocol reduces system administration workload, allowing devices to be added to the network with little or no manual configurations.

Applicability: Dynamic Host Configuration Protocol is a way to manage network parameter assignment from a single DHCP server, or a group of DHCP servers arranged in a fault-tolerant manner. Even in small networks, Dynamic Host Configuration Protocol is useful because it can make it easy to add new machines to the local network.
DHCP is also recommended even in the case of servers whose addresses rarely change, so that if a server needs to be readdressed changes can be made in as few places as possible.

DHCP can be used to directly assign addresses to servers and desktop machines and through a Point-to-Point Protocol (PPP) proxy, to dialup and broadband on-demand hosts, as well as for residential Network address translation (NAT) gateways and routers.

NAT: In computer networking, network address translation is a technique of transceiving network traffic through a router that involves re-writing the source and/or destination IP addresses and usually also the TCP/UDP port numbers of IP packets as they pass through. Checksums (both IP and TCP/UDP) must also be rewritten to take account of the changes.

Common Object Request Broker Architecture (CORBA)

The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) that enables software components written in multiple computer languages and running on multiple computers to work together.It is a mechanism in software for normalizing the method-call semantics between application objects that reside either in the same address space (application) or remote address space (same host, or remote host on a network).

CORBA uses an interface definition language (IDL) to specify the interfaces that objects will present to the outside world. CORBA then specifies a “mapping” from IDL to a specific implementation language like C++ or Java.

IDL:
An interface description language or interface definition language or IDL, is a specification language used to describe a software component's interface. IDLs describe an interface enabling communication between software components that do not share a language - for example, between components written in C++ and components written in Java.

IP Address and Classes

The Internet Protocol moves data between hosts in the form of datagrams. Each datagram is delivered to the address contained in the Destination Address (word 5) of the datagram's header. The Destination Address is a standard 32-bit IP address that contains sufficient information to uniquely identify a network and a specific host on that network.
An IP address contains a network part and a host part, but the format of these parts is not the same in every IP address. The number of address bits used to identify the network, and the number used to identify the host, vary according to the prefix length of the address. There are two ways the prefix length is determined: by address class or by a CIDR address mask.
Address Classes
Originally, the IP address space was divided into a few fixed-length structures called address classes. The three main address classes are class A, class B, and class C.
1. If the first bit of an IP address is 0, it is the address of a class A network. The first bit of a class A address identifies the address class. The next 7 bits identify the network, and the last 24 bits identify the host. There are fewer than 128 class A network numbers, but each class A network can be composed of millions of hosts.
2.If the first 2 bits of the address are 1 0, it is a class B network address. The first 2 bits identify class; the next 14 bits identify the network, and the last 16 bits identify the host. There are thousands of class B network numbers and each class B network can contain thousands of hosts.
3.If the first 3 bits of the address are 1 1 0, it is a class C network address. In a class C address, the first 3 bits are class identifiers; the next 21 bits are the network address, and the last 8 bits identify the host. There are millions of class C network numbers, but each class C network is composed of fewer than 254 hosts.
4. If the first 4 bits of the address are 1 1 1 0, it is a multicast address. These addresses are sometimes called class D addresses, but they don't really refer to specific networks. Multicast addresses are used to address groups of computers all at one time. Multicast addresses identify a group of computers that share a common application, such as a video conference, as opposed to a group of computers that share a common network.
5. If the first four bits of the address are 1 1 1 1, it is a special reserved address. These addresses are sometimes called class E addresses, but they don't really refer to specific networks. No numbers are currently assigned in this range.

My understanding about com object.

com object acts as an interface between one application and another. Eg. our VB application is connected to the database through ADODB com object. This com object acts as an interface between our VB application and the database.

Virtual Sticky Notes

Hi got this information from The hindu news paper.
Now, virtual sticky notes
New York: Software that enables mobile phone users to obtain location-specific, real-time information, either actively or passively, from other users across the world has been developed by a team led by an Indian-American Professor at Duke University.
The rapid convergence of social networks, mobile phones and global positioning technology has given Duke University engineers the ability to create “virtual sticky notes” — site-specific messages that people can leave for others to pick up on their mobile phones.
Romit Roy Choudhury, Assistant Professor at Duke’s Pratt School of Engineering, said: “Every mobile phone can act as a telescope lens providing real-time information about its environment to any of the three billion mobile phones worldwide.” It will be as if every participating mobile phone works together allowing each individual access to information throughout the virtual network.