Write short notes on 1. Package 2. AWT vs Swing 3. Marshals and unmarshals of parameters

 1. Package:

A package in Java is a mechanism of organizing related classes and interfaces into a single unit. It helps in avoiding naming conflicts and also provides better readability and maintainability of the code. Packages are declared using the 'package' keyword at the top of a source file, and their name should correspond to the directory structure in which the package's classes are stored.

2. AWT vs Swing:

AWT (Abstract Window Toolkit) and Swing are two Java libraries used for creating graphical user interfaces (GUI). AWT was the first GUI toolkit included with Java and provides a set of classes and methods for creating GUI components such as windows, buttons, and text fields. Swing, on the other hand, is an extension of AWT and provides more powerful and flexible components than AWT. Swing components are implemented entirely in Java, which makes them more platform-independent and customizable than AWT components.

Difference between AWT and Swing

3. Marshals and Unmarshals of Parameters:

Marshalling and Unmarshalling are techniques used to transfer objects across a network or between different applications. Marshalling is the process of converting a Java object into a format that can be transmitted over the network or stored in a file. Unmarshalling is the process of converting the transmitted or stored data back into a Java object.

Marshalling involves converting the object into a sequence of bytes, which can then be transmitted over a network or stored in a file. The sequence of bytes contains information about the object's data and its structure, including its fields, methods, and other properties. Unmarshalling involves reading the transmitted or stored data and reconstructing the original object from the information contained in the data.

Marshalling and unmarshalling of parameters are commonly used in remote procedure calls (RPC), where a client application calls a method on a remote server and passes parameters to it. The parameters are marshalled and sent to the server, which unmarshals them and uses them to execute the requested method. After the method is executed, the result is marshalled and sent back to the client, which unmarshals it and uses it in its own application logic.