Java interview questions and Answers

Applet is a Java program that gets embedded into web pages using the APPLET or OBJECT tag and runs inside the browser.

It works at the client side, and is hosted on a web server. Applets make websites dynamic and entertaining.

This is a good question concerning core java interview questions for experienced professionals. finalize method is called by the Garbage Collector before performing the clean-up activity. Clean-up activity refers to the process of de-allocating all the resources, such as database connection and network connection, associated with an object.

instanceof operator is used in object reference variables. In this, the operator will check the class type or interface type of an object.

It is written as follows:

( Object reference variable ) instanceof (class/interface type)

By Read-only class we are referring to the "IMMUTABLE" concept. You can begin by defining a class so that no methods can cause changes to the internal state.

In such classes, aliasing will have no impact because its internal state is read-only.

Here are the steps for creating a package:

• Choose a name for the package
• On top of every source file, put the package statement with the package name. Source file must contain classes and types that you want in the package.
• Package statement is the first line of source file.
• You can only have one package statement in each file
• It applies to all file types.

Exception handling allows developers to handle runtime errors caused by exceptions. One way to handle exceptions is to print a simple message for users that help them correct the error that occurs due to bad data sent by the user.

Exception handling ensures the flow of the application does not break.

System class has useful fields, such as static members, that are related to the environment. This class is provided with standard streams like input, output and error.

These streams can be used to access the properties and environment variables that are externally defined.