Java Environment

A Java Virtual Machine (JVM) is a collection of programs and data structures that uses a virtual machine to execute computer programs and scripts.

Java Environment

Java Environment

     

 

A Java Virtual Machine (JVM) is a collection of programs and data structures that uses a virtual machine to execute computer programs and scripts. The JVM is distributed along with a set of standard class libraries which implement the Java API (Application Programming Interface). The virtual machine and API have to be consistent with each other and are therefore bundled together as the Java Runtime Environment. Java Virtual Machines mainly run Java (programming language) code, while a JVM can also runs other programming languages. JVM is the main component of the Java Platform. Java can be both middleware as well as a platform as JVMs are available for many hardware and software platforms. Since the JVM converts the source code into the byte code that why java is said to be platform independent language means once the source is compiled (i.e. once the source code converted into the bytecode) the complied code can run any platform regarding the platform must have the JVM. The JVM also provides us a unique features known as Automated Exception Handling. This Automated Exception Handling feature provides us a 'root-cause' debugging information for every software error (exception) regardless of the source code.
 
Execution environment

  
Programs that are to be run on a JVM must be compiled into a standardized portable binary format, that usual comes in the form of .class files. A program may have several classes in different files. Multiple class files are packaged together in a .jar file so that large programs can be made easier for their distribution.

Java runtime environment executes .class or .jar files,  follow JVM instruction set by interpreting it. Java runtime environment can also use just-in-time compiler (JIT) such as Sun's HotSpot.