I already read about it on google- "runtime environment is the environment in which a program or application is executed". But it is not clear.
I was basically starting with node js and came to know about it being a runtime environment of javascript. The same term was mentioned a lot of times when I was reading about c++ and its features. But what is and environment referring to here?Is it the environment that editors like visual studio code and others provide for languages and who is managing and providing this environment for us?
as you may have guessed or idea as the word meaning the term "runtime environment" refers to the infrastructure and resources necessary for executing a program or application that means it includes the software and hardware components required to run the code effectively as you asked the case of programming languages like JavaScript and C++, the runtime environment provides the necessary tools and libraries to execute the code.
as you also asked in context of java - the java runtime environment (JRE) is responsible for executing Java applications. It consists of the Java Virtual Machine (JVM), which interprets and executes the Java bytecode, and the Java Class Library, which provides a set of pre-compiled classes and methods for common tasks.
The JRE manages memory allocation, garbage collection, and other low-level operations required for running Java programs. It also provides access to system resources, such as files, network connections, and input/output streams. further more as all language require to ultimately convert in to byte code so when you write a Java program, you compile it into bytecode using the Java Development Kit (JDK). The bytecode is then executed by the JRE, which translates it into machine code that can be understood by the underlying operating system. for more you can read it from JRE .
in case of Node. js it uses the Chrome V8 JavaScript engine in place of the JVM and the Node API or modules instead of Java classes. here more on that .C,C++ generate .exe files which is specific for the OS and Java generates byte code which is not specific to any OS (also keep in mind jvm is itself written in C,C++ ). also if you dig more please read it What are the differences between LLVM bitcode and Java bytecode?