A02 - JRE + JDK + JVM
B. JRE = java runtime envoirnment
= program and predefined library
1. java package class
2. runtime library
3. jvm , java virtual machine ( verifiy byte code and executes it, plateform dependent )
= class loader
= memory area
= executes engines
1. class library and supporting files
2. no development tools
3. run the program
4. jre = jvm + java package class + runtime libraries
