in src/main/java/org/apache/maven/shared/invoker/MavenCommandLineBuilder.java [243:255]
protected void setProperties(InvocationRequest request, Commandline cli) {
Properties properties = request.getProperties();
if (properties != null) {
for (Entry<Object, Object> entry : properties.entrySet()) {
String key = (String) entry.getKey();
String value = (String) entry.getValue();
cli.createArg().setValue("-D");
cli.createArg().setValue(key + '=' + value);
}
}
}