Java Concepts

Casting of Reference Types in Java

Casting is the conversion of data of one type to another type either implicitly or explicitly.  

Casting happens for both primitive types and reference types. 

If the casting operation is safe, java will do automatic type casting. This is called implicit type casting. 

If java can't be sure whether the casting will be safe, java will not do automatic casting, but programmer can do the casting if he is sure about the outcome. This is called explicit type casting.

A Quick Introduction to Programming for Java Beginners

I assume that you are here to learn Java programming language and you don't have any programming language experience. So let us quickly get introduced to some important terms, starting with, what programing is and why you do it.

A programmer create software through a process called programming or coding. The purpose of programming is to develop an executable computer program that will automate performing a specific task or solving a given problem.

[Bullets] Compiled vs Interpreted Languages

  1. compiler is a computer program that transforms source code written in a programming language into another computer language, often in a binary form, that is understood by the computer platform.

  2. A compiler usually transforms a high-level programming language to machine code specific to a platform, so that it can then be directly executed in that platform.

Path vs Classpath

The PATH environment variable contains a set of directories within the file system that the operating system uses to find executable files. When you type a command in command prompt, operating system will look for the corresponding executable in the current folder and then it will look inside every folder mentioned in the PATH environment variable in order. For instance, when you type javac, OS will search for java.exe within the current folder and then every folder mentioned inside in the PATH environment variable in order.

Casting of Primitives in Java

Casting is the conversion of data of one type to another type either implicitly or explicitly.  

Casting happens for both primitive types and reference types. 

If the casting operation is safe, java will do automatic type casting. This is called implicit type casting. 

If java can't be sure whether the casting will be safe, java will not do automatic casting, but programmer can do the casting if he is sure about the outcome. This is called explicit type casting.

What is Java?

Java is a high level programming language that follows the object oriented principles. Java is syntactically and structurally modeled after C/C++. 

Introduction to Just-In-Time Compilation and Hotspot JVM

Just-In-Time compilation

Java is not purely a traditional compiled or interpreted language, but tries to come in between them. 

In Java, source code is saved in files with .java extensions. This source code is then compiled into a intermediate platform independent byte code, and this form has a .class extension. This .class file is then executed by Java’s JVM. 

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