Java String Concatenation

Question

I have a issue with my java code. i asked the same question yesterday. I got answer but sorry it was my fault. My question is not clear.

I have code looks like this:

Answer 1

Additions to Thierry-Dimitri Roys response.

StringBuilder sb = new StringBuilder();
ProximityTarget prox;
float latitude;
float longitude;
float radius;

//Use for-each if you process all elements
for(Target target : geo.getTargets()){

  //Use literal string first to avoid NullPointerException
  if("ProximityTarget".equalsIgnoreCase(target.getTargetType())){
    prox        = (ProximityTarget)geo.getTargets(i);
    latitude    = prox.getGeoPoint().getLatitudeInMicroDegrees()); 
    longitude   = prox.getGeoPoint().getLongitudeInMicroDegrees());
    radius      = prox.getRadiusDistanceUnits();

    //Checking sb every loop is not a good practice.
    //Instead try removing first delimeter after for-loop
    sb.append("|circle:" + longitude + ":" + latitude + ":" + radius);
  } 
}

//AFAIK StringBuilder has no isEmpty Method.
//So use length method
if (sb.length() > 0){
    sb.deleteCharAt(0);
}

String result = sb.toString();