- Enviroment variables are system wide values which can be accessed by applications.
- PATH variable is used to inform the system where it can find command line programs
- JAVA_HOME informs Java about where it can find the Java and Javac commands
- CLASSPATH informs Java about what libraries are available.
- Enviroment variables can be set by using the SET or EXPORT commands.
- JAR files are zipped folders of class files.
- JAR files store completed applications or libraries.