Which provides runtime environment for java byte code to be executed?

The JRE is the Java Runtime Environment. It is a package of everything necessary to run a compiled Java program, including the Java Virtual Machine (JVM), the Java Class Library, the java command, and other infrastructure. However, it cannot be used to create new programs. The JDK is the Java Development Kit, the full-featured SDK for Java. It has everything the JRE has, but also the compiler ( javac) and tools (like javadoc and jdb). It is capable of creating and compiling programs. Usually, if you only care about running Java programs on computer you will only install the JRE. It's all you need. On the other hand, if you are planning to do some Java programming, you need to install the JDK instead. Sometimes, even if you are not planning to do any Java development on a computer, you still need the JDK installed. For example, if you are deploying a web application with JSP, you are technically just running Java programs inside the application server. Why would you need the JDK then? Because the application server will convert JSP into Java servlets and needs to use the JDK to compile the servlets. I am sure that there are more examples. I don't have information to be completely sure, but my guess would be that either you didn't really set the classpath correctly, or you set the classpath for a different classloader than the one that ended up using your code. What makes lib/ext different from classpath extension is that lib/ext will affect any java app that uses that parti...

JVM(Java Virtual Machine) Jvm stands for Java Virtual A virtual machine is just a virtual representation of a Physical computer. We run this virtual machine on some physical machine or computer. this physical computer is called the Host machine and the virtual machine is called the guest machine. WORA-Write Once Use Anywhere. It means when you write any Java code and compiles it, the compiler converts the .java file into a .class file (byte-code ).and this .class file, you can share with anybody and they can run this file on their machine with their respective operating system Jre(Don't worry,u will understand this line later in the article). But it is not possible with other languages such as c or C++. Thus, Java programs are called WORA. Now, Here comes in Picture, Jvm. Jvm takes the .class file (also called byte code ) and starts to execute the program line by line. This Java virtual machine internally uses an Interpreter and executes the Java code line by line. If any error exists in any line, then after that line remaining code will not be executed. note: JVM only by itself cannot execute a Java program .it needs the help of some inbuilt files called library files and an environemnt to execute the program. Here comes in picture, Java Runtime Environment. Sun MicroSystems(the creator of Java ) provides another technology called Jre(Java runtime environment) to help JVM execute the program. There is much more to JVM, but we will not deep dive too much into that. JRE(Jav...

I am studying for a Java certificate and I got a question that I know it could be really basic. However, I am not sure: Question: Which statement is true about Java bytecode? a) It can run on any platform. b) It can run on any platform only if it was compiled for that platform. c) It can run on any platform that has the Java Runtime Environment. d) It can run on any platform that has a Java compiler. e) It can run on any platform only if that platform has both Java Runtime Environment and Java compiler. I think (c) is the correct answer, assuming that the Java Runtime Environment is the interpreter. The answer would be C. Java bytecode is already the compiled form of the Java source code, and the Java compiler is only available with the Java Software Development Kit (SDK). Once code has been compiled, it does not need to be compiled again. All the system needs is the Java Runtime Environment (JRE) because the JRE is able to interpret the bytecode and run it on the system. The Java Runtime Environment (JRE) is a software package which bundles the libraries (jars) and the Java Virtual Machine, and other components to run applications written in the Java. JVM is just a part of JRE distributions. To execute any Java application, you need JRE installed in the machine. It’s the minimum requirement to run Java applications on any computer. So, my answer would be C.

Main task of JVM: • Search and locate the required files. • Convert byte code into executable code. • Allocate the memory into ram • Execute the code. • Delete the executable code. JRE (Java RunTime Environment):Â Â Â Â Â Â Â Â JVM + java runtime libraries + java package classes (e.g. util, lang etc). JRE provides class libraries and other supporting files with JVM. It not provide any development tool like compiler, debugger etc. JDK (Java Development Kit): Â Â Â Â Â Â JRE+ development tool (compiler, debugger etc.). JDK contains tools to develop the application and JRE to execute the application. Next Topic: Java Coding Guidelines. Previous Topic: JVM architecture details. Related Topics: Programming language overview. Overview of Java. Java features JVM (java virtual machine) architecture details. Difference between JVM, JRE and JDK. Java Coding Guidelines.

Java Development Kit (JDK) is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), an interpreter/loader (Java), a compiler (javac), an archiver (jar), a documentation generator (Javadoc), and other tools needed in Java development. Now we need an environment to make a run of our program. Henceforth, JRE stands for “Java Runtime Environment” and may also be written as “Java RTE.” The Java Runtime Environment provides the minimum requirements for executing a Java application; it consists of the Java Virtual Machine (JVM), core classes, and supporting files. Now let us discuss JVM, which stands out for java virtual machines. It is as follows: • A specification where the working of Java Virtual Machine is specified. But implementation provider is independent to choose the algorithm. Its implementation has been provided by Sun and other companies. • An implementation is a computer program that meets the requirements of the JVM specification. • Runtime Instance Whenever you write a java command on the command prompt to run the java class, an instance of JVM is created. Before proceeding to the differences between JDK, JRE, and JVM, let us discuss them in brief first and interrelate them with the image below proposed. • Development Tools(to provide an environment to develop your java programs) • JRE (to execute your java program). 2. JRE (Java Runtime Environment) is an installation package that pro...