JRE and JDK are two completely different tools. This is the main difference between them. JDK is specifically designed for Java programmers.
It includes all the tools necessary to do Java programming. Javac is used to convert Java source files into class files. You cannot develop Java applications and programs without JDK.
JDK comes with its own JRE. Executing a Java program using the Java command will execute the JRE first found in System Path.
The PYPL Popularity of Programming Language Index predicts that Java will be the world's second most popular language in 2024.
Oracle reports that Java is widely used, with over 69% of full-time developers worldwide and 51 billion active Java Virtual Machines (JVMs) deployed.
What Makes Java Programming Languages So Popular?
Java's platform independence feature is the first and most important reason. Java Virtual Machine makes it platform-independent, meaning that programmers who have developed their software on one platform can run it on any platform or OS regardless of its underlying configuration.
Java is a WORA-compliant software that can be run anywhere and written once. Java also provides security against eavesdropping and tampering, impersonation and virus threats.
Java provides multithreading, which allows us to create multiple threads in any process that works independently or simultaneously.
Java's performance is impressive, in addition to these features. JIT (Just In Time Compiler), which can compile only the method being called, and not the entire program, is used.
This makes development much more efficient and saves time. Java is a versatile programming language that offers a variety of applications due to its high performance.
Java is the most widely used programming language for developing android apps. It's also used in scientific and web applications. These are just a few of the reasons Java is so popular.
Java Development: Why Use It?
Programmers can learn Java quickly. Java is the most popular programming language. Java is still very popular in the industry.
Java technology is still used by most governments, healthcare, defense, education, and other websites. It is worthwhile to learn Java. Java can be a career choice if you are interested in it. You can do almost everything with Java.
Java developers must understand the differences between JDK, JRE, and JVM in order to successfully manage their development environment and runtime execution.
Top Java Features
Simple
Java is an easy programming language that is simple and understandable, unlike other popular programming languages.
Javasoft people wanted simplicity in their design, as it must work on devices with less memory or resources. Java uses the same variable syntax as C and C++, so programmers switching to Java won't have any problems with syntax.
The concept of pointers has been removed completely from Java, which can confuse programmers and make them more vulnerable to security.
Object-Oriented
Java is an Object Oriented Programming Language. Everything in Java is written in terms of classes and objects. What is an object? An object is a real-world entity that can represent people, places, or things and can be distinguished from other objects.
Each object we see has a state or behavior. My mobile phone is an example of a real-world entity. It states color, model, brand, and camera quality.
These properties can be represented by reference variables. Mobile is also associated with actions such as calling, messaging, and photography. These actions can be represented using the Java method.
We now know what an object looks like and how it behaves. What is the class like? What is the class definition like? A group of objects that display the same behavior and state will be classified as one class.
Although different brands make various smartphones, such as Samsung, Apple and Vivo, Oppo, or Xiaomi, they all fall under the same category, Mobile Phones. Below are the main concepts for any Object Oriented Programming Language.
- Class and Object
- Encapsulation
- Abstraction
- Inheritance
- Polymorphism
Platform Independent
Javasoft people have set out to create a language that can be used on all platforms. Platform refers to a type of operating system and technology.
Java allows programmers to create their programs on any machine with any configuration and then execute them on any machine with a different configuration.
Java's Java source code is compiled into bytecode. This bytecode is not tied to any platform. This bytecode can only be understood by the Java Virtual Machine installed on our system.
We were referring to the fact that each operating system has its own JVM version, capable of reading and converting bytecode into a machine-native language.
This decreases the time and effort required to write system-specific code. Programmers now write programs once and compile them to generate bytecode. Then, they can export it wherever they want.
Portable
Thanks to the WORA (Write Once Run Anywhere) concept and platform-independent feature, Java is portable. Developers can now use Java programming to achieve the same results on every machine by writing only one line of code.
This is due to JVM and bytecode. Let's say you write Java code. The code is then converted to equivalent bytecode, which can only be readable by JVM.
There are different versions of JVM available for different platforms. Windows machines use their own JVM version, while Linux uses its own.
MacOS also has its own JVM version. If you send your bytecode to any machine, the JVM on that machine will convert it into the appropriate machine code.
This allows programmers to focus on productivity and development rather than writing different codes for different platforms.
Robust
Java Programming Language is strong, meaning it can handle unexpected terminations of programs. There are two reasons for this.
First, it has an important and useful feature called Exception handling. Java code will not cause any harm if an exception is raised. In contrast, programs written in lower-level languages will crash.
Java's memory management features are another reason Java is so strong. Java, unlike other low-level languages, provides a Java runtime Garbage Collector that collects all unused variables.
The garbage collector runs under JVM and finds any unutilized variables and objects. It then removes them from memory to make them more space-free.
However, in other languages, no program handles memory management. Instead, programmers are responsible for allocating and distributing memory spaces.
Otherwise, the program could crash.
Secure
Security is a top concern in today's world. Hacking is possible because every device can be connected using the Internet.
Our Java application needs security. Java provides security features for programmers. Java can help with security problems such as virus threats, tampering and impersonation.
Java offers encryption and decryption options to protect your data from eavesdropping or tampering via the Internet.
An Impersonation is a person pretending to be someone else on the Internet. Here's how to solve it. The digital signature is the key to impersonation.
This file contains personal identification information, but it's not readable.
Java can create digital signatures. A virus is a program capable of harming our systems. It is usually spread via.exe image and video files.
However, it cannot be spread by text files.
Java bytecode, which is also a file, is text (yes,.class is a file with non-human readable format). Our JVM can distinguish viruses from other programs, so we are still safe even if someone tries to put virus code into a bytecode format file.
JVM will throw an exception if a virus is detected in a bytecode format and stop execution.
Interpreted
You have probably learned that programming languages use either an interpreter or a compiler. However, the Java programming language employs both a compiler and an interpreter.
Java programs are compiled to create bytecode files. The JVM then interprets the bytecode during execution. JIT compilers are also used by JVM to speed up execution.
Multi-Threaded
Thread is a lightweight, independent subprocess that runs within a program (i.e., process) and shares resources.
Multithreading is when multiple threads are running simultaneously. Multithreading is a term that describes multiple tasks being run simultaneously in many applications. For example, Google Docs has spell check and autocorrect tasks running while you type.
Multithreading is also used by servers to respond to multiple client requests. You can create threads using Java in one of two ways: implementing Runnable or extending the Thread Class.
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What's Java Development Kit (JDK)?
Oracle JDK is one of the most popular Java development tools. Since the dawn of time, it has been used for building Java applications.
OpenJDK is a new platform for Java development that the Java community has a choice. JDK is Java Development Kit. It's a platform that allows you to create applications and applets. Java applications.
JDK is a physical presence that contains JRE + development tools. Multiple versions of JDK can be installed on the same computer.
Java developer skills can use JDK on macOS, Windows, and Linux.
JDK allows them to write and run Java software. It is an implementation of one of the Java Platforms that Oracle Corporation releases.
- Micro Edition.
- Enterprise Edition.
- Standard Edition.
The JDK includes a JVM (Java Virtual Machine), as well as a few other tools such as Java (a loader/interpreter), javac (a compiler), Javadoc (a document generator), and the Jar (an archiver).
Complete the Java app development process.
Development And Popularity
Oracle Corporation developed Oracle JDK entirely. On the other hand, OpenJDK was created with contributions from Oracle, OpenJDK, and the Java Community.
OpenJDK was also created by prominent companies like Red Hat, Azul Systems, and IBM.
OpenJDK vs. Oracle JDK is close in popularity and the number of users. Oracle JDK was once highly praised for its stability, maturity, and reliability.
It was the first choice for any company that used Java Development Kits in their toolkits. Notable examples include IntelliJ IDEA and Android Studio. However, both have now switched to OpenJDK, built on JetBrains versions.
Fedora Linux, Ubuntu Red Hat Enterprise, and Red Hat Enterprise offer OpenJDK as their Java SE implementation. This rapid rise in popularity was anticipated by Java developers in many ways.
Performance
They share the same platform-specific building process, so there aren't any technical differences. The Oracle JDK performs better in terms of responsiveness and JVM performance.
Because the target group is large enterprises that are unable or willing to compromise performance, it is much more focused on stability.
However, OpenJDK users have had issues with stability and performance in the past. However, this is now fixed. OpenJDKs performance is improving rapidly.
Thanks to the many contributions of the OpenJDK community, the OpenJDK versions have become steadily more stable.
Features Available
OpenJDK has more features and options than Oracle JDK. OpenJDK doesn't have the Flight Recorder feature or Java Mission Control.
It also has Application Class-Data sharing capabilities. Oracle JDK also offers faster rendering and better Garbage collection options. OpenJDK has a Font Renderer integrated, and all the standard options are available.
However, Oracle JDK users would prefer to use it.
A Variety of Products Can Be Built
Java is a general-purpose programming language. It is, therefore, suitable for many applications. Java programmers have many language options, including desktop applications and websites with backend programming.
They can also create Android games and apps.
Read More: All About Java Application Development Process 2023
What Is The Java Runtime Environment (JRE)?
JRE is a package that contains JVM and a class library. It allows you to run Java applications autonomously. However, it can execute the code.
JRE is bundled with Java Development Kit (JDK), which provides a complete experience for creating applications. The discussion on Reddit about JDK vs JRE shed light on the differences between Java development environments and their different functions.
JRE = Java Virtual Machine + Class Libraries (For Running Java Applications)
- The JRE includes class libraries, JVM, and associated files. Additional tools, such as debuggers for Java development, are not included in the JRE.
- JRE also includes important class classes such as util math, math, and other runtime libraries.
Specifications For JRE
- JRE (Java Runtime Environment) is a collection of tools used to make JVM run, such as Java Plugin, Web Start and other deployment tools.
- JRE is the sole tool capable of efficiently running Java-based code; however, this does not permit program development or creation.
- JRE includes integration libraries such as JDBC (Java Database Connectivity), JNDI [Java Naming and Directory Interface], RMI (Remote Method Invocation), and many others.
- It is a Java HotSpot application designed to work alongside JVM.
JRE includes more than just Java Virtual Machine; it also contains various methods and tools with features to make creating Java applications as smooth and effective as possible.
Deployment Solutions
Install the JRE to activate applications and gain assistance for future Java updates. Install Java Web Start and Java Plugin as part of JRE to make life easier when updating software applications.
Development Tools: Developers can leverage JRE toolkits to improve user experiences. There are:
- Java 2D: An Application Programming Interface, commonly referred to as API, allows developers to generate two-dimensional Java drawings with interactive user interfaces, special effects games and animation.
- Abstract Windows Toolkit (AWT): A GUI, or Graphical User Interface, is a set of tools for building objects such as scroll bars, buttons, and windows.
- Swing: Another lighter GUI provides users with customizable widgets.
Language And Utility Libraries: JRE (Java Runtime Environment) includes packages essential to Java app development, versioning, monitoring and other tasks such as:
- Collections Framework: An integrated architecture featuring various interfaces designed to streamline and store application data more effectively.
- Concurrency Tools: Java frameworks tools with high performance threaded applications support.
- Preferences API: Simple, universally compatible API that enables multiple users on one computer to establish groups of preferences for applications.
- Logging: Reports that provide log data such as configuration or security issues as well as performance concerns which can then be further analysed are invaluable tools for further examination of problems in an organization's operations.
- Java Archive: Platform-independent JAR format that combines multiple files together for quicker download speeds and to reduce file sizes significantly.
What Does JRE Do?
JRE, JDK and JRE work in unison to form an efficient runtime environment on almost all operating systems for running Java apps.
The JRE structure comprises several components.
- ClassLoader: The Java ClassLoader dynamically loads classes used by Java programs as needed from memory until needed for execution.
- Bytecode Verifier: Before Java code can be run through an interpreter, its format and accuracy must first be validated by a bytecode verifier. If any violation occurs regarding security and integrity of system components, such as invalidating classes altogether if applicable - otherwise loaders would just keep running them regardless.
- Interpreter: Once loaded, Java interpreter launches JVM application so the Java program runs natively on that machine.
Difference Between The JDK Platform And JRE Platform
JDK is necessary if you are programming Java, as this package includes it. Additionally, online gamers who frequently access games require it; JRE does not come included with this bundle; we have provided below an explanation of these differences between JDK (and JRE).
Are the JDK and JRE the same thing? Yes. JDK is a software development environment used for developing enterprise Java apps on various Java platforms like Standard Edition, Enterprise Edition Micro Edition and Standard Micro Edition.
JRE is part of JDK that fulfills minimum requirements to run these Java apps; thus making this distinction between them quite clear.
JDK
- JDK (Java Development Kit) allows developers to easily build Java applications. In addition, various development tools like compilers and debuggers come included as part of this kit.
- The JDK contains both JRE and various development tools such as Java interpreter, compiler, applet viewer and document viewer. The JDK runs across Java SE/EE/ME platforms.The JDK package comprises the JRE as well as command line tools used for custom Java development, such as debuggers and compilers - essential tools when developing apps or applets.
- The JDK package comprises the JRE as well as command-line tools such as debuggers and compilers - essential or helpful tools when developing applets or apps.
- JDK=JRE Development Tools.
JRE
- JRE (Java Runtime Environment) is a virtual machine for running Java applications.
- The Java Development Kit (JDK) includes the Java Virtual Machine, core classes, and various libraries that allow for developing Java applications. Although the JRE is part and parcel of the JDK, it can also be downloaded and used.
- JRE stands for its Java Virtual Machine. This is where Java applications run. You also get Applet execution browser plugs.
- You don't have to worry about development if you are a client. You only need an environment that allows you to run the program and achieve the results JRE promises.
- JRE=JVM and Library Class.
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Conclusion
Java programmers need to know the differences between JDK (JRE) and JDK (JRE). There are many differences between them.
It is easy to get lost in trying to figure out what the topic is. These distinctions will help you see things rationally. Because JDK is a software development tool, the distinctions between JRE and JDK are well-known.
It also allows you to create a Java-based program.