in src/main/java/org/apache/commons/exec/environment/DefaultProcessingEnvironment.java [130:140]
public synchronized Map<String, String> getProcEnvironment() throws IOException {
if (procEnvironment == null) {
procEnvironment = createProcEnvironment();
}
// create a copy of the map just in case that
// anyone is going to modifiy it, e.g. removing
// or setting an evironment variable
final Map<String, String> copy = createEnvironmentMap();
copy.putAll(procEnvironment);
return copy;
}