Chage your code like,

        JSONArray c = jsonObject.getJSONArray("Channel_12");  //Change your code from here
        JSONArray array = c.getJSONArray(0);
        String data = c.getString(1);
        Log.i("#Values", array.getString(0) + "\t" + data);

See my result,

you need a recursive function.

function iterateTree(object) {
  if (!object) { //recursion stop criteria || you need to implement what your stop criteria is
     return;
  }
  //doSomthingWithObject();
  iterateTree(object.children);
}

I'm sure you figure it out how to use it in java.

Create a new JSONObject each time, inside the loop.

JSONArray outer = new JSONArray();
    JSONObject js = null;
    List<String> str = new ArrayList<String>();
    str.add("London");
    str.add("Tokyo");
    str.add("Washington");

    int res = 3;


    for(int i=0;i<res;i++){
        js= new JSONObject();
        js.put("Value", i);
        js.put("Name", "John");
        js.put("Cities", str);
        outer.add(js);          
    }           
    System.out.println(outer);

Also, you'll probably get the same issue if changing cities anytime, so unless they will always remain the required three, create a new list for every object.

You can do it using ecmascript 5's forEach method:

land.forEach(function(entry){ 
      console.log(entry.name + " : " + entry.value) 
} );

or use jquery to support legacy web browsers:

$.each(land,function(index,entry) {
     console.log(entry.name + " : " + entry.value)
});

I Assume you have List messages :

Here is how you can browse through all children with both recursion and iterative way :

List<Message> messages = //you already have that

System.out.println("Using Recusion : ");

for (Message message : messages) {
    printMessage(message);
}

System.out.println("Using Iterative : ");

Stack<Message> stack = new Stack<>();
stack.addAll(messages);

while (!stack.empty()) {
    Message item = stack.pop();
    System.out.println(item.getId() + ":" + item.getUser_id() + ":" + item.getMessage());
    for (Message chidren : item.getChildren()) {
        stack.push(chidren);
    }
}

and here is the printMessage method :

public static void printMessage(Message pmessage) {
    System.out.println(pmessage.getId() + ":" + pmessage.getUser_id() + ":" + pmessage.getMessage());
    for (Message message : pmessage.getChildren()) {
        printMessage(message);
    }
}

Maybe this will help:

JSONObject jsonObject = new JSONObject(contents.trim());
Iterator<String> keys = jsonObject.keys();

while(keys.hasNext()) {
    String key = keys.next();
    if (jsonObject.get(key) instanceof JSONObject) {
          // do something with jsonObject here      
    }
}

If your data is structured as a nested loop then you're going to need to iterate through both loops. You can apply some Java8 streaming if you want to shorten it though.

import java.util.ArrayList;

public class NestedStreamTest {

  public static void main(String[] args) {
    //Following is for example data
    var nest = new ArrayList<ArrayList<Integer>>();
    for(int i = 0; i < 10; i++) {
      var list = new ArrayList<Integer>();
      nest.add(list);
      for(int j = 0; j < 10; j++)
        if(j % 2 == 0)
          list.add(j);
        else
          list.add(null);
    }
    
    //Actual looping starts here
    nest.stream() //Loop through the nest
      .flatMap(list -> list.stream()) //Loop through each list in the nest
      .filter(value -> value != null) //Only allow values which are not null to continue
      .forEach(value -> System.out.println(value.toString())); //Print each filtered value
  }
}

The problem in the above code is JSONObject obj = new JSONObject(); initialised only one but you need to create inside the loop. This code gives the expected output as you want:

public static void main(String[] args) throws JSONException {

    JSONObject index = new JSONObject();
    JSONObject jsonRecipe = new JSONObject();


    JSONObject metadataReq = new JSONObject();
    metadataReq.put("technology","Ceramics");
    metadataReq.put("material","Nylon");
    metadataReq.put("color","Green");


    JSONArray keys = metadataReq.names();
    for (int i = 0; i < metadataReq.length (); i++) {
       String key = keys.getString (i);
       String val = metadataReq.getString (key);

       String j = Integer.toString(i);

       JSONObject obj = new JSONObject();
       obj.put("attribute", key);
       obj.put("value", val);
       obj.put("mandatory", "rule");

       index.put(j, obj);
       jsonRecipe.put("metadata", index);
    }

    System.out.println(jsonRecipe);

}

Maybe you're not using the latest version of a JSON for Java Library.

json-simple has not been updated for a long time, while JSON-Java was updated 2 month ago.

JSON-Java can be found on GitHub, here is the link to its repo: https://github.com/douglascrockford/JSON-java

After switching the library, you can refer to my sample code down below:

public static void main(String[] args) {
    String JSON = "{\"LanguageLevels\":{\"1\":\"Pocz\\u0105tkuj\\u0105cy\",\"2\":\"\\u015arednioZaawansowany\",\"3\":\"Zaawansowany\",\"4\":\"Ekspert\"}}\n";

    JSONObject jsonObject = new JSONObject(JSON);
    JSONObject getSth = jsonObject.getJSONObject("LanguageLevels");
    Object level = getSth.get("2");

    System.out.println(level);
}

And as JSON-Java open-sourced, you can read the code and its document, they will guide you through.

Hope that it helps.