Grabbing an environment variable from Jenkins

gistfile1.java

// Assuming environment is an EnvVars object, and mergeOptions is an arbitrary object that, when I call getMergeOptions(), returns the branch I'm merging with - Which can either be a string - or an environment variable, $some_var


String mergeTarget = "";
if ( environment.get(mergeOptions.getMergeTarget()) != null ) {
  mergeTarget = environment.get(mergeOptions.getMergeTarget().substring(1));
} else {
  mergeTarget = mergeOptions.getMergeTarget();
}


vs...

mergeTarget = environment.expand(mergeOptions.getMergeTarget());

// I'm assuming the second one is the correct way to do it here :-)