import java.util.ArrayList; import java.util.HashSet; import java.util.List; public class Demo { public static void main(String[] argv) { List<Integer>list1 = new ArrayList<Integer>(); list1.add(100); list1.add(200); list1.add(300); list1.add(400); list1.add(400); list1.add(500); list1.add(600); list1.add(600); list1.add(700); list1.add(400); list1.add(500); HashSet<Integer>set = new HashSet<Integer>(list1); List<Integer>list2 = new ArrayList<Integer>(set); System.out.println("List after removing duplicate elements:"); for (Object ob: list2) System.out.println(ob); } }
import java.time.Duration; public class Demo { public static void main(String[] args) { Duration d1 = Duration.ofDays(20); Duration d2 = Duration.ofHours(100); Duration d3 = Duration.ofMinutes(150); System.out.println("Milliseconds in 20 days = "+d1.toMillis()); System.out.println("Milliseconds in 100 hours = "+d2.toMillis()); System.out.println("Milliseconds in 150 minutes = "+d3.toMillis()); } }
import java.io.File; public class Demo { public static void main(String[] args) throws Exception { File myFile = new File("input.txt"); myFile.createNewFile(); myFile.setReadOnly(); if (myFile.canWrite()) { System.out.println("Writable!"); } else { System.out.println("Read only mode!"); } // set file to writable myFile.setWritable(true); if (myFile.canWrite()) { System.out.println("Writable!"); } else { System.out.println("Read only mode!"); } } }
import java.util.ArrayList; import java.util.ListIterator; public class Demo { public static void main(String[] args) { ArrayList<String>arrList = new ArrayList<String>(); arrList.add("Jack"); arrList.add("Tom"); arrList.add("Brad"); arrList.add("Amy"); arrList.add("Ben"); arrList.add("Peter"); arrList.add("Katie"); arrList.add("Tim"); System.out.println("List..."); for (String str: arrList){ System.out.println(str); } ListIterator<String>iterator = arrList.listIterator(); iterator.next(); iterator.remove(); System.out.println("Updated List..."); for (String str: arrList){ System.out.println(str); } } }
import java.util.Arrays; import java.util.Collections; import java.util.List; public class Demo { public static void main(String[] argv) throws Exception { String[] arr = new String[] { "P", "W", "g", "K", "H", "t", "E" }; List<String>list = Arrays.asList(arr); System.out.println("List = "+list); Collections.sort(list); System.out.println("Case Sensitive Sort = "+list); Collections.sort(list, String.CASE_INSENSITIVE_ORDER); System.out.println("Case Insensitive Sort = "+list); } }
import java.util.ArrayList; import java.util.TreeSet; import java.util.List; public class Demo { public static void main(String[] args) { List<String>ls = new ArrayList<String>(); ls.add("A"); ls.add("B"); ls.add("C"); ls.add("D"); ls.add("D"); ls.add("E"); ls.add("F"); ls.add("G"); ls.add("E"); TreeSet<String>set = new TreeSet<String>(); set.addAll(ls); System.out.println("TreeSet = "+set); } }
import java.util.Collections; import java.util.Iterator; import java.util.List; public class Demo { public static void main(String[] args) { List<Integer>list = Collections.nCopies(10, 100); Iterator<Integer>iterator = list.iterator(); System.out.println("Displaying 100 multiple times..."); while (iterator.hasNext()) System.out.println(iterator.next()); } }
import java.time.LocalDate; import java.time.ZoneOffset; import java.util.Date; public class Demo { public static void main(String[] args) { LocalDate date = LocalDate.now(); System.out.println("Date = "+date); System.out.println("Date (UTC) = "+Date.from(date.atStartOfDay().toInstant(ZoneOffset.UTC))); } }
import java.time.LocalDate; import java.time.ZoneOffset; import java.util.Date; public class Demo { public static void main(String[] args) { LocalDate date = LocalDate.now(); System.out.println("Date = "+date); ZoneOffset timeZone = ZoneOffset.UTC; System.out.println(Date.from(date.atStartOfDay().toInstant(timeZone))); } }
import java.util.ArrayList; import java.util.LinkedHashMap; import java.util.List; import java.util.Map; public class Demo { public static void main(String[] args) { Map<String, String>map = new LinkedHashMap<String, String>(); map.put("1", "Katie"); map.put("2", "Peter"); map.put("3", "Amy"); map.put("4", "Kane"); map.put("5", "Colin"); map.put("6", "Andre"); map.put("7", "Pollard"); map.put("8", "David"); map.put("9", "Jofra"); map.put("10", "Akila"); List<String>list = new ArrayList<String>(); list.addAll(map.keySet()); System.out.println("Keys..."); for (String str: list) { System.out.println(str); } } }
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