Please help in this code..

Question

Hi,
I am developing one small program. Which has one inner class in parent class. I am using object [] array of that inner class. like thisPreferredRoomsItem maxPercentagePrefRooms[] = new PreferredRoomsItem[solutionOfTimeTable.MAX_ACTIVITIES];  
        for (int j = 0; j < solutionOfTimeTable.nInternalActivities; j++) {           
            maxPercentagePrefRooms[j].percentage=-1.0;
            maxPercentagePrefRooms[j].prefferedRooms.clear(); // test it.                                  
            double maxPercentage = -1;
            double minNRooms = INF;        
            for(PreferredRoomsItem it:activitiesPreferredRoomsList){ // check this code. this is incorrect/.
            if(maxPercentage<it.percentage || (maxPercentage==it.percentage && minNRooms>it.prefferedRooms.size())){           
                maxPercentage = it.percentage;              
                minNRooms = it.prefferedRooms.size();
                maxPercentagePrefRooms[j] = it;
            } In inner class PreferredRoomsItem it has two member variables. And then I am using iteration with for loop. When I am using this line-->maxPercentagePrefRooms[j]. it gives me nullpointerexception. Please help.
It is urgent.
Thanks in advance.

Answer 1

You still need to instantiate the Object in each array index.
for (int j = 0; j < solutionOfTimeTable.nInternalActivities; j++) {           
             maxPercentagePrefRooms[j] = new PreferredRoomsItem();
            //...