I need a way to do the same operation with much less code. This will help me to understand Java in much better way.
OUTPUT of the below code will be:
new, boy, 3pm, to

```
public class substring {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    String str= "a new, boy with new haircut boy, 3pm to boy 8pm margian 3pm to ghost";
    String concant = "";
    int occurance =0;
    str = str.replaceAll(",", "");
    System.out.println(str);
    String[] subStr = str.split("\\s");
    for(String sub:subStr)
    {
        for (String sub1:subStr) {
            if(sub.equals(sub1))
            { 
                 occurance++;

                if(occurance>=2)
                {
                    if(!concant.contains(sub))
                    {
                        if(concant!= "")
                          concant = concant +", "+ sub;
                        else
                            concant = sub;

                    }
                }
            }

        }   
        occurance = 0;  
    }
    System.out.println(concant);

}

}

```