public class HelloWorld {\n public static void main(String[] args) {\n System.out.println(\"HelloWorld!\");\n }\n}<\/pre>\nFeatures of Java<\/h3>\n
![\"Features](\"https:\/\/techvidvan.com\/tutorials\/wp-content\/uploads\/sites\/2\/2020\/06\/Features-of-Java-tv.jpg\")
<\/a><\/p>\nAccording to the TIOBE index, the rank of Java constantly remains in the top 2 languages because of its robust and security features. Let us discuss the features of Java that make it so popular among all the programming languages.<\/p>\n
Following are some of the Java features that make it so popular in the programming world:<\/p>\n
1. Simple<\/h4>\n
Java is a simplified version of the C++ language, and therefore, it is familiar also. Moreover, it eliminates all redundant and unreliable code. There is no support of pointers, preprocessor header files, operator overloading, and multiple inheritances in Java. This makes Java easier as compared to C++.<\/p>\n
2. Object-oriented<\/h4>\n
Java is an object-oriented language and mainly focuses on objects rather than processes. Java follows the Object-Oriented Programming (OOP) concept like:<\/p>\n
\n- Objects<\/li>\n
- Classes<\/li>\n
- Inheritance<\/li>\n
- Encapsulation \/ Data hiding<\/li>\n
- Abstraction<\/li>\n
- Polymorphism<\/li>\n<\/ul>\n
Note-<\/strong> Java is not a pure object-oriented language as it allows the use of primitive data types.<\/p>\n3. Platform-independent<\/h4>\n
Java is a platform-independent language as the source code of Java can run on multiple operating systems. Java programs can run on any machine or the operating system that does not need any special software installed.<\/p>\n
Although the JVM needs to be present in the machine. Java code compiles into bytecode(.class file), which is platform-independent. We can run this bytecode on Windows, Linux, Mac OS, etc.<\/p>\n
4. Portable<\/h4>\n
Java is portable because Java code is executable on all the major platforms. Once we compile Java source code to bytecode, we can use it in any Java-supported platform without modification, unlike other languages that require compiling the code for each platform.<\/p>\n
Java is portable because we can carry bytecode over to any other platform it runs on.<\/p>\n
5. Robust<\/h4>\n
The following features make Java robust and powerful:<\/p>\n
\n- There is no use of explicit pointers in Java.<\/li>\n
- Java provides a strong memory management<\/li>\n
- It supports Automatic garbage collection, so there is no need to delete the unreferenced objects manually.<\/li>\n
- Java also provides exception handling and type-checking mechanisms.<\/li>\n<\/ul>\n
6. Secure<\/h4>\n
Java is a secure language because of the following reasons:<\/p>\n
\n- Java does not support pointers that make Java robust and secure.<\/li>\n
- All Java programs run inside a virtual machine sandbox.<\/li>\n
- The Java Runtime Environment(JRE) has a classloader that dynamically loads the classes into the Java Virtual Machine.<\/li>\n
- The Bytecode Verifier of Java inspects the parts of code for checking the illegal code that can bypass access.<\/li>\n
- The Security Manager of Java decides what resources to allot to a class. Such access includes reading and writing into files.<\/li>\n
- Java also helps us develop virus-free systems.<\/li>\n<\/ul>\n
7. Multithreaded and Interactive<\/h4>\n
Java is a multithreaded language that means it can handle different tasks simultaneously. Java supports multithreaded programs, in which there is no need to wait for one task to finish for another to start.<\/p>\n
This feature of Java significantly improves the interactive performance of graphical applications.<\/p>\n
History of Java<\/h3>\n
Java first appeared in the year 1995 as Oak. They also decided to call this language the project Green, before it could find its popularity as Java by finding its roots in coffee, which in turn is attributed to Java- an island in Indonesia.<\/p>\n
\n- The first version 1.0 of Java came in 1996 when Sun Microsystems promised the principle of WORA (Write Once, Run Anywhere) property.<\/li>\n
- Then Java 2 (J2SE 1.2) was introduced in December 1998-1999. J2EE(Java Enterprise Editions) was for enterprise applications.<\/li>\n
- In 2006, Sun renamed new J2 versions as Java EE, Java ME, and Java SE.<\/li>\n
- September 2018 marked the release of Java SE 11 (LTS).<\/li>\n
- March 2019 marked the release of Java SE 12 (LTS).<\/li>\n
- On September 10th, 2019, Java SE 13 was released.<\/li>\n
- Java SE 14 came in March 2020, which is the latest version of Java.<\/li>\n<\/ul>\n
Java Architecture \u2013 Java Environment<\/h3>\n
Now, we will learn the architecture of Java and its main components like JRE, JVM, and JDK. The following diagram shows the architecture of Java:<\/p>\n
![\"Java](\"https:\/\/techvidvan.com\/tutorials\/wp-content\/uploads\/sites\/2\/2020\/06\/Java-Architecture-\u2013-The-Java-Environment-TV.jpg\")
<\/a><\/p>\n1. JVM (Java Virtual Machine)<\/h4>\n
Java Virtual Machine(JVM) provides a runtime environment in which bytecode executes. Java Virtual Machine is platform-dependent. The JVM performs the following tasks:<\/p>\n
\n- Loading the code<\/li>\n
- Verifying the code<\/li>\n
- Executing the code<\/li>\n
- Providing a runtime environment<\/li>\n<\/ul>\n
2. JRE (Java Runtime Environment)<\/h4>\n
JRE is a collection of tools that allow the development of applications and provide a runtime environment to run Java programs. JVM is a part of JRE. JRE is also platform-dependent.<\/p>\n
JRE facilitates the execution of Java programs and comprises JVM, Runtime class libraries, User interface toolkits, Deployment technologies, Java plugin, etc.<\/p>\n
3. JDK (Java Development Kit)<\/h4>\n
Java Development Kit is a kit that provides the environment to develop and execute a Java program. JDK includes development tools to provide an environment to develop Java programs.<\/p>\n
It also contains JRE that runs your Java code. JDK also contains other resources like the interpreter\/loader, compiler (javac), an archiver (jar), and a documentation generator (Javadoc). These components together help you to build Java programs.<\/p>\n
Java Development Kit includes-<\/p>\n
\n- appletviewer (for viewing Java applets)<\/li>\n
- javac (Java compiler)<\/li>\n
- java (Java interpreter)<\/li>\n
- javap (Java disassembler)<\/li>\n
- javah (for C header files)<\/li>\n
- javadoc (for creating HTML files)<\/li>\n
- jdb (Java debugger)<\/li>\n<\/ul>\n
Proceeding ahead in this java tutorial, let us see advantages and limitations of java.<\/p>\n
Advantages of Java<\/h3>\n\n- It is a platform-independent language because we can run Java code on any machine without any special software.<\/li>\n
- It is an object-oriented language because of its classes and objects. Object-oriented programming increases the ease of code development and increases efficiency.<\/li>\n
- It is a secure language, and the reason behind being secure is pointers, Java does not use pointers.<\/li>\n
- It supports multithreading; we can execute many programs simultaneously.<\/li>\n
- Java is a robust language as it has many features like automatic garbage collection, no use of explicit pointers, exception handling, etc.<\/li>\n
- Java is a high-level programming language that makes it easy to learn and understand.<\/li>\n
- It provides efficient memory management.<\/li>\n<\/ul>\n
Disadvantages of Java<\/h3>\n\n- Java is a high-level language. Therefore Java must deal with the compilation and abstraction levels of a virtual machine.<\/li>\n
- Java exhibits poor performance because of the garbage collector, wrong caching configuration, and deadlocks, among processes.<\/li>\n
- Java has very few GUI(Graphical User Interface) builders like Swing, SWT, JSF, and JavaFX.<\/li>\n
- We could end up writing long, complicated code if we try to carry out a simple set of activities. This affects the readability of code.<\/li>\n<\/ul>\n
Difference Between C++ and Java<\/h3>\n
The main difference between C++ and Java is that Java is an Object-oriented language, while C++ just adds an object-oriented feature to C.<\/p>\n
Let\u2019s see what makes Java different from C++:<\/p>\n
\n- No support for operator overloading in Java as in C++.<\/li>\n
- Java does not provide template classes as in C++.<\/li>\n
- Java does not support explicit pointers, but C++ supports.<\/li>\n
- There is no support for global variables in Java as in C++.<\/li>\n
- Java uses a finalize () function and C++ uses destructor function.<\/li>\n
- There are no header files in Java as in C++.<\/li>\n
- Java does not support \u201cgoto\u201d statements, unique C++.<\/li>\n
- C++ supports multiple inheritances through classes, but Java supports the same through interfaces.<\/li>\n
- Java does not support \u201ccall-by-reference\u201d; it only supports \u201ccall-by-value.\u201d<\/li>\n
- There is no support for structures and unions in Java, as in C++.<\/li>\n
- Java does not support the \u201cvirtual\u201d keyword.<\/li>\n<\/ul>\n
Let\u2019s compare a hello world program in C++ and Java.<\/p>\n
Example of C++ Programming Language-<\/strong><\/p>\n#include <iostream>\nusing namespace std;\nint main()\n{\ncout << \"HelloWorld!\";\nreturn 0;\n}\n<\/pre>\nExample of Java Programming Language-<\/strong><\/p>\npublic class Hello {\n public static void main(String[] args) {\n System.out.println(\"Hello, World!\");\n }\n}<\/pre>\nJava Language and the Internet<\/h3>\n
Now, we will discuss how the Internet and Java are related to each other. The diagram below shows the relationship between Java and the Internet.<\/p>\n
![\"Java](\"https:\/\/techvidvan.com\/tutorials\/wp-content\/uploads\/sites\/2\/2020\/06\/Java-Language-Internet-tv.jpg\")
<\/a><\/p>\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Java Tutorial \u2013 Java Language and Internet<\/strong><\/p>\nJava is often called the Internet language as HotJava was the first application program in Java. HotJava is a Web browser that runs applets on the Internet.<\/p>\n
Internet users can create applets using Java and run them locally using HotJava. Java applets make the Internet a true extension of the storage system on local computers.<\/p>\n
Java Programming and World Wide Web<\/h3>\n
Do you know how Java and the World Wide Web(WWW) are related? World Wide Web is an information system where any information or file has Uniform Resource Locators (URLs), and hypertext links interlink. We can access WWW with the help of the Internet.<\/p>\n
The Internet and Java both had the same philosophy, and therefore they were incorporated with each other easily. It was possible only because of Java by providing features like graphics, animation, games, and a wide range of special effects in WWW.<\/p>\n