Retrieves the value of an environment variable.
Retrieves the value of an environment variable or else returns the specified fallback value.
Retrieves the value of an environment variable or else returns the specified optional fallback value.
Retrieves the values of all environment variables.
Retrieves the value of the system-specific line separator.
Retrieves the values of all system properties.
Retrieves the value of a system property.
Retrieves the value of a system property or else return the specified fallback value.
Retrieves the value of a system property or else return the specified optional fallback value.