Java Dynamic Programming

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In this tutorial, you will learn about Java programming, why and how you can learn Java. You will also learn about JDK, JRE and JVM, and the differences between them.

What is Java ?

Java is a popular and powerful general-purpose programming language. Java is a object oriented programming language designed to have as less implementation dependencies as possible. It can be used as a language as well as a platform for software application development on networked computer systems. It is used to develop desktop and mobile applications, big data processing, embedded systems, and so on. According to Oracle, the company that owns Java, Java runs on 3 billion devices worldwide, which makes Java one of the most popular programming languages. Java was originally developed by James Gosling at Sun Microsystems, which has since been acquired by Oracle, and released in 1995 as a core component of Sun Microsystems’ Java platform.

Characteristics of Java

1. Write Once Run Anywhere – Java programs are platform independent and once written can be run on different platforms by different interpreters without modifying the code.
2. Object Oriented – Java is object oriented programming language which makes the code flexible, reusable and very close to the real world.
3. Speed – Efficient and properly optimized Java code is almost as fast as lower level languages like C++ and faster than Python, PHP, etc.
4. Security – Java offers many security features to make its programs safe and secured.
5. Multimedia – Java supports multimedia and is favourable for internet environment.

Why learn Java ?

1. Java is a platform-independent language. We can write Java code in one platform and run it in another platform.
2. Java is a general-purpose language with a wide range of applications. It’s used for developing mobile and desktop applications, big data processing, embedded systems, and so on.
3. Java is an object-oriented programming language. It helps in code reusability.
4. As Java is close to C++ and C#, it makes it easy for programmers to switch to and from Java.
5. Java is easy to learn and simple to use, open-source and free, secure, fast and powerful.

How learn Java ?

1. Read and learn step by step Java tutorials from our website.
2. Analyse and solve the detailed examples provided on our website.
3. Visit the official Java documentation on Oracle website.

What is JDK ?

JDK (Java Development Kit) is a software development kit required to develop applications in Java. When you download JDK, JRE is also downloaded with it. In addition to JRE, JDK also contains a number of development tools (compilers, JavaDoc, Java Debugger, etc).

What is JVM ?

JVM (Java Virtual Machine) is an abstract machine that enables your computer to run a Java program. When you run the Java program, Java compiler first compiles your Java code to bytecode. Then, the JVM translates bytecode into native machine code (set of instructions that a computer’s CPU executes directly). Java is a platform-independent language. It’s because when you write Java code, it’s ultimately written for JVM but not your physical machine (computer). Since JVM ​executes the Java bytecode which is platform-independent, Java is platform-independent.

What is JRE ?

JRE (Java Runtime Environment) is a software package that provides Java class libraries, Java Virtual Machine (JVM), and other components that are required to run Java applications. JRE is the superset of JVM.

Relationship between them

JRE is composed of JVM and Java Class Libraries. JRE along with Compilers, Debuggers and JavaDoc form JDK. Programs written in Java (.java) are compiled (by javac) into Java Byte Code (.class) which is then interpreted by the Java interpreter for that specific platform. This interpreter which behaves like a virtual processor chip is known as Java Virtual Machine. The Java Byte Code is the machine instruction for the JVM, and is platform independent. The JVM is machine dependent.