if (inputString.length()<=0)
        return "";


    String ans ="";

    for (int i =0;i<inputString.length();i++)
    {
        int count =1;
        char c = inputString.charAt(i);
        for (int j =i+1;j<inputString.length();j++)
        {
            if (inputString.charAt(j)!=inputString.charAt(i)){

                break;}

            else
            count++;
            i++;
        }
        ans+= count+""+c;
    }


    return ans;

}
....

Problem 2 Encoding Decoding String
Encode or Decocde string with given key , operation 1 is encoding 2 is decoding

Example
1
Open
123

output
Oppeeen

Example 2
2
Oppeeen
123

output
Open

...
 static String ans ="";
public static boolean Encoding(String msg, String Key)
{
    //String ans = "";
    int i=0,j=0;

    while (i<msg.length() && j<Key.length())
    {
        int n=0;
        try {
            n = Integer.parseInt(Key.charAt(j) + "");
        }
        catch (Exception e)
        {
            return false;
        }
        char c = msg.charAt(i);

        if (n<0)
            return false;

        for(int m =0;m<n;m++)
            ans  = ans+ ""+ c;
        i++;j++;
    }

       if (i<msg.length())
           ans += msg.substring(i,msg.length());

       return true;
}

public static boolean Decoding(String msg, String Key)
{

    int i=0,j=0;

    while (i<msg.length() && j<Key.length())
    {
        int n=0;
        try {
              n = Integer.parseInt(Key.charAt(j) + "");
        }
        catch (Exception e)
        {
            return false;
        }
        char c = msg.charAt(i);
        int count=1;
        int m = i +1;

        for (;m<msg.length();m++)
        {
            if (c!=msg.charAt(m))
                break;

            count++;
            i++;
        }

        if (count!=n)
            return false;
        else
            ans += c;
        i++;j++;

    }

    if (i<msg.length())
        ans += msg.substring(i,msg.length());

    return true;
}


public static String secureChannel(int operation, String message, String key) {

    ans ="";
    if(message.length()<=0)
        return "-1";
    if (operation==1 && Encoding(message,key))
     return ans;

    else if (operation==2 && Decoding(message,key))
        return ans;

    return "-1";
}