Idiot Programmer

 Sort ArrayList of custom Objects by property in java Do Check My Utility Class Video: Example: import java.util.Collections; import java.util.Comparator; import java.util.ArrayList; //Customized Sorting public class Test{     public static void main(String[] args) {         ArrayList<String> l = new ArrayList<>();         l.add("z");         l.add("a");         l.add("k");         l.add("n");         // l.add(new Integer(10));//CCE         //l.add(null);//NPE         System.out.println("Before Sorting: "+l);//[z, a, k, n]         Collections.sort(l,new MyComparator());         System.out.println("After Sorting: "+l);//[z, n, k, a]     } } class MyComparator implements Comparator{     public int compare(Object obj1,Object obj2){         String s1 = (String)obj1;         String s2 = obj2.toString();         return s2.compareTo(s1);     } } o/p: Before Sorting: [z, a, k, n] After Sorting: [z, n, k, a]

How to sort an ArrayList?  Collection class defines the following two sort methods    1)public static void sort(list l)     to sort acc. to default natural sorting order     in this list should contains homogeneous object and comparable object otherwise we will     get classCastexception     list should not contain null otherwise we will get nullPointerException     2)public static void sort(List l,Comparator c)     to sort based on customized sorting Do Check My Video On Utility Classes: Example: import java.util.ArrayList; import java.util.Collection; import java.util.Collections; public class Test{          public static void main(String[] args) {         ArrayList<String> l = new ArrayList<>();         l.add("z");         l.add("a");         l.add("k");         l.add("n");         // l.add(new Integer(10));//CCE         //l.add(null);//NPE         System.out.println("Before Sorting: "+l);//[z, a, k, n]         Collection