Java Preparation for interviews

In this post I am going to present the required stuff for Attending interviews on Java.

Post is written keeping in mind about beginners.

Simply Java is ?

Java a high-level programming language with following features

object oriented

multi threaded

platform independent

Robust

secure

Dynamic

Portable

White paper with more details about the above words.

Java programs will be written in plain text files saved as .java and then what happens -

In the above compiler is javac

.class contains only bytecode (a machine's language 0 & 1's )which can only be understood by JVM(machine is - Java Virtual Machine).

The name itself is saying that its a virtual machine but not a physical ..

Java Code is one - generated class file is also only one but the JVM's are multiple; to execute it on multiple machines.

Java platform is a software only platform which runs on other hardware based platforms.(win,Unix - SW+HW=win platform or unix platform)

But Java runs on top of any.

Java platform = JVM + JAPI

JAPI : Java Application Programming interface

I love JAVA because - "its write once run anywhere".

"Hello World " well known word while starting any programming language.

The correct signature is public static void main(String[] args)

When declaring the main method, which modifier must come first, public or static?

They can be in either order, but the convention is public static.

The main method defines a single parameter, usually named args, whose type is an array of String objects.

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