how to pass json object from java to javascript?

myJSON.trackpoints is an array of two objects. If you want to write it as HTML you could do something like this:

function writeCoordinates(coords) {
    document.writeln('<div>lat = ' + coords.latitude);
    document.writeln(', lon = ' + coords.longitude + '</div>');
}

int len = myJSON.trackpoints.length;
for (int i = 0; i < len; i++) {
    writeCoordinates(myJSON.trackpoints[i]);
}

BTW: JSON is really useful when you're using AJAX requests, but for "normal" requests it's better to put plain Java objects into the model, for example:

Spring Controller:

List<Coordinate> trackpoints = ...
model.addAttribute("trackpoints", trackpoints);

JSP:

<c:forEach items="${trackpoints}" var="coord">
    <div>lat = ${coord.latitude}, lon = ${coord.longitude}</div>
</c:forEach>

given, that the Coordinate class has the methods getLatitude() and getLongitude(). That method in the Spring controller can even be used for both "normal" and AJAX requests, by using a JSON encoder, like Jackson, and the ContentNegotiatingViewResolver.

Take a look at: http://jsfiddle.net/AHue8/4/

I guess the take-away here is that you need to specify which element in the trackpoint object you want and you countrol how those are displayed in the browser. Since a "trackPoint" isn't a primitive data type (it's an object with 2 data elements latitude and longitude), the browser doesn't know how to interpret it, so you have to tell it how.

I had the same need: passing a list of Java objects from Spring boot controller to Javascript code (to be handled as Json objects), I have found a solution:

In Java

Get the list of MyObject, convert it to an equivalent textual Json representation and append it to the model, the result is something like below:

import com.google.gson.Gson;

@Service
public class MyService {

    private static final Gson GSON = new Gson();
    
    
    public void getData(final Model model) {
        List<MyObject> myObjectList = getObjects...
        model.addAttribute("myObjectListAsJsonText", GSON.toJson(myObjectList));
    }
    
}

In JSP/HTML page (Not in a separated JS file)

Add a script block to get the Json representation of MyObject list and convert it to a Json array that can be processed by Javascript:

<title>MyApp | Main page</title>
<link rel="shortcut icon" href="resources/img/favicon.ico">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<script  th:inline="javascript">
    var myObjectListAsJson = '${myObjectListAsJsonText}';
    var myObjectJsonArray = JSON.parse(myObjectListAsJson);
</script>

In Any separated Javascipt file of the same page

Can access the global variable myObjectJsonArray that is holding the Json array of MyObject items, like:

function processMyObjectJsonArray() {
    for (var index = 0; index < myObjectJsonArray.length; index++) {
        var myObjectJsonItem = myObjectJsonArray[index];
        console.log("Can access ID attribute of an item of MyObject array:" + myObjectJsonItem.id);
    }
}