At first, let us create and array of strings:String[] strArr = { "ABCD", "AB", "ABCDEFG", "ABC", "A", "ABCDE", "ABCDEF", "ABCDEFGHIJ" };Now, for shortest to longest pattern, for example A, AB, ABC, ABCD, etc.; get the length of both the string arrays and work them like this:Arrays.sort(strArr, (str1, str2) -> str1.length() - str2.length());The following is an example to sort array of strings by their lengths with shortest to longest pattern:Exampleimport java.util.Arrays; public class Demo {    public static void main(String[] args) {       String[] strArr = { "ABCD", "AB", "ABCDEFG", "ABC", "A", "ABCDE", "ABCDEF", "ABCDEFGHIJ" };       ... Read More

Following is our integer array:Integer[] arr = {20, 50, 100, 150, 200, 250, 300, 350, 400, 500};Now convert the above Integer array to List:List list = new ArrayList(Arrays.asList(arr));Now, to sort the above Integer list in reversed order:Comparator initialComp = Integer::compare; Comparator revComp = initialComp.reversed(); Collections.sort(list, revComp);The following is an example to sort Integer list in reversed order:Exampleimport java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.Comparator; import java.util.List; public class Demo {    public static void main(String[] args) {       Integer[] arr = {20, 50, 100, 150, 200, 250, 300, 350, 400, 500};       List list = new ... Read More

In this article, we will learn how to sort lists containing null values in Java and ensure these nulls are kept at the bottom while upper elements remain in order. This can be done using Comparator.nullsLast, which sorts the non-null elements and places all null elements at last. Problem Statement A list of strings with some string values and nulls is given. Write a Java program to sort a list placing nulls in the end. Input Initial List = ("Jack", null, "Thor", null, "Loki", "Peter", null, "Hulk") Output Initial List = [Jack, null, Thor, null, Loki, Peter, null, Hulk] List ... Read More

Let us create a list first with string elements. Some of the elements are null in the List:List list = Arrays.asList("Jack", null, "Thor", null, "Loki", "Peter", null, "Hulk");Now, sort the above list and place nulls first with nullsFirst:list.sort(Comparator.nullsFirst(String::compareTo));The following is an example to sort a List that places nulls first:Exampleimport java.util.Arrays; import java.util.Comparator; import java.util.List; public class Demo {    public static void main(String... args) {       List list = Arrays.asList("Jack", null, "Thor", null, "Loki", "Peter", null, "Hulk");       System.out.println("Initial List = "+list);       list.sort(Comparator.nullsFirst(String::compareTo));       System.out.println("List placing nulls first = "+list); ... Read More

Yes, we can sort a list with Lambda. Let us first create a String List:List list = Arrays.asList("LCD", "Laptop", "Mobile", "Device", "LED", "Tablet");Now, sort using Lambda, wherein we will be using compareTo():Collections.sort(list, (String str1, String str2) -> str2.compareTo(str1));The following is an example to sort a list with Lambda in Java:Exampleimport java.util.Arrays; import java.util.Collections; import java.util.List; public class Demo {    public static void main(String... args) {         List list = Arrays.asList("LCD", "Laptop", "Mobile", "Device", "LED", "Tablet");       System.out.println("List = "+list);       Collections.sort(list, (String str1, String str2) -> str2.compareTo(str1));       System.out.println("Sorted List ... Read More

Let’s say the following is our stream:Stream.of("u2", "h9", "s8", "l3")Now, map to get the substring:.map(s -> s.substring(1))Convert to int and find the minimum:.mapToInt(Integer::parseInt) .min()The following is an example to Map and get substring and convert to int:Exampleimport java.util.stream.Stream; public class Demo {    public static void main(String[] args) throws Exception {    Stream.of("u2", "h9", "s8", "l3")       .map(s -> s.substring(1))       .mapToInt(Integer::parseInt)       .min()       .ifPresent(System.out::println);    } }Output2

To add JList to Scroll pane in Java, use JScrollPane:JList list = new JList(sports); JScrollPane scrollPane = new JScrollPane(list);After that set it to Container:Container contentPane = frame.getContentPane(); contentPane.add(scrollPane, BorderLayout.CENTER);The following is an example to add JList to Scroll pane:Examplepackage my; import java.awt.event.*; import java.awt.*; import javax.swing.*; class SwingDemo extends JFrame {    static JFrame frame;    static JList list;    public static void main(String[] args) {       frame = new JFrame("JList Demo");       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);       String sports[]= {"Tennis", "Archery", "Football", "Fencing", "Cricket", "Squash", "Hockey", "Rugby"};       list = new JList(sports);     ... Read More

To store string array in JList, at first create String array list:String sports[]= { "Football", "Fencing", "Cricket", "Squash", "Hockey", "Rugby"};Now, set it to JList:JList list = new JList(sports);The following is an example to store string array in JList:Examplepackage my; import java.awt.event.*; import java.awt.*; import javax.swing.*; class SwingDemo extends JFrame {    static JFrame frame;    static JList list;    public static void main(String[] args) {       frame = new JFrame("JList Demo");       SwingDemo s = new SwingDemo();       JPanel panel = new JPanel();       String sports[]= {"Football", "Fencing", "Cricket", "Squash", "Hockey", "Rugby"}; ... Read More

To set single selection for JList, use DefaultListSelectionModel and set it to SINGLE_SELECTION:String values[]= { "One", "Two", "Three", "Four", "Five", "Six"}; JList list = new JList(values); list.setSelectionMode(DefaultListSelectionModel.SINGLE_SELECTION);The following is an example to set the selection mode for JList only for single selection:Examplepackage my; import java.awt.event.*; import java.awt.*; import javax.swing.*; class SwingDemo extends JFrame {    static JFrame frame;    static JList list;    public static void main(String[] args) {       frame = new JFrame("JList Demo");       SwingDemo s = new SwingDemo();       JPanel panel = new JPanel();       String values[]= { ... Read More

To select the first item in JList, use setSelectionInterval() method:String values[]= { "One", "Two", "Three", "Four", "Five", "Six"}; JList list = new JList(values); int begn = 0; int end = 0; list.setSelectionInterval(begn, end);The following is an example to select the first item in JList:Examplepackage my; import java.awt.event.*; import java.awt.*; import javax.swing.*; class SwingDemo extends JFrame {    static JFrame frame;    static JList list;    public static void main(String[] args) {       frame = new JFrame("JList Demo");       SwingDemo s = new SwingDemo();       JPanel panel = new JPanel();       String values[]= ... Read More