Remove substring with given offset from string

I'm trying to implement a function able to remove some substrings from a given string using their starting and ending offset. I've got an ArrayList of objects like this:

"This","0","4"
"This is","0","8"
"some","39","43"

Here my class:

package com.giacomomarangoni;

import java.io.IOException;
import java.util.ArrayList;

public class GNTestClass {

    private static String removeSubFromString(String line,int start,int end, int decrement){
        /* DECREMENT BASED ON SUBSTRING REMOVED */
        start = start - decrement;
        end = end - decrement;
        retu line.substring(0,start)+line.substring(end);
    }

    private static ArrayList<GNEntityObject> populateArrayList(){
        ArrayList<GNEntityObject> entities = new ArrayList<>();
        GNEntityObject e1 = new GNEntityObject();
        e1.setWord("This");
        e1.setStartOffset(0);
        e1.setEndOffset(4);
        entities.add(e1);
        /* START COMMENT HERE TO REMOVE OVERLAPPING */
        GNEntityObject e2 = new GNEntityObject();
        e2.setWord("This is");
        e2.setStartOffset(0);
        e2.setEndOffset(8);
        entities.add(e2);
        /* END COMMENT */
        GNEntityObject e3 = new GNEntityObject();
        e3.setWord("some");
        e3.setStartOffset(39);
        e3.setEndOffset(43);
        entities.add(e3);
        retu entities;
    }

    public static void main(String[] args) throws IOException {
        ArrayList<GNEntityObject> entities = populateArrayList();
        String testString = "This is a text, I would like to remove some string in the right way";
        int dec = 0;
        for (GNEntityObject e : entities){
            testString = removeSubFromString(testString, e.getStartOffset(), e.getEndOffset(), dec);
            /* UPDATE DECREMENT BASED ON SUBSTRING LENGTH */
            dec += (e.getEndOffset() - e.getStartOffset());
        }
        System.out.println(testString);
    }
}

if substrings are not overlapped everything works, otherwise they don't. I know why, but I'm not able to overcame this particular case. Hope someone will help. Thank you.