Let’s say the following is our string array and we need to sort it:String[] str = { "Tom", "Jack", "Harry", "Zen", "Tim", "David" };Within the sort() method, create a customized comparator to sort the above string. Here, two strings are compared with each other and the process goes on:Arrays.sort(str, new Comparator < String > () {    public int compare(String one, String two) {       int val = two.length() - one.length();       if (val == 0)       val = one.compareToIgnoreCase(two);       return val;    } });Exampleimport java.util.Arrays; import java.util.Comparator; public class Demo ... Read More

Create two time instants:Instant time1 = Instant.now(); Instant time2 = Instant.now().plusSeconds(50);Use between() to get the duration between two time instants:long resMilli = Duration.between(time1, time2).toMillis();Exampleimport java.time.Duration; import java.time.Instant; public class Demo {    public static void main(String[] args) {       Instant time1 = Instant.now();       Instant time2 = Instant.now().plusSeconds(50);       long resMilli = Duration.between(time1, time2).toMillis();       System.out.println("Duration between two time intervals = "+resMilli);    } }OutputDuration between two time intervals = 50000

At first, set the Clock:Clock clock = Clock.systemUTC();Now, create LocalDateTime:LocalDateTime dateTime = LocalDateTime.now(clock);Exampleimport java.time.Clock; import java.time.LocalDateTime; public class Demo {    public static void main(String[] args) {       Clock clock = Clock.systemUTC();       System.out.println("Clock = "+Clock.systemDefaultZone());       LocalDateTime dateTime = LocalDateTime.now(clock);       System.out.println("LocalDateTime = "+dateTime);    } }OutputClock = SystemClock[Asia/Calcutta] LocalDateTime = 2019-04-19T09:29:50.605820900

At first, set the date:LocalDateTime dateTime = LocalDateTime.of(2019, Month.SEPTEMBER, 6, 20, 10);Now, format the datetime as BASIC_ISO_DATE format:String str = dateTime.format(DateTimeFormatter.BASIC_ISO_DATE);Exampleimport java.time.LocalDateTime; import java.time.Month; import java.time.format.DateTimeFormatter; public class Demo {    public static void main(String[] args) {       LocalDateTime dateTime = LocalDateTime.of(2019, Month.SEPTEMBER, 6, 20, 10);       System.out.println("DateTime = "+dateTime);       String str = dateTime.format(DateTimeFormatter.BASIC_ISO_DATE);       System.out.println("Formatted date = "+str);    } }OutputDateTime = 2019-09-06T20:10 Formatted date = 20190906

At first, set the date:LocalDateTime dateTime = LocalDateTime.of(2019, Month.SEPTEMBER, 9, 10, 20);Now, format the datetime as ISO_WEEK_DATE format:String str = dateTime.format(DateTimeFormatter.ISO_WEEK_DATE);Exampleimport java.time.LocalDateTime; import java.time.Month; import java.time.format.DateTimeFormatter; public class Demo {    public static void main(String[] args) {       LocalDateTime dateTime = LocalDateTime.of(2019, Month.SEPTEMBER, 9, 10, 20);       System.out.println("DateTime = "+dateTime);       String str = dateTime.format(DateTimeFormatter.ISO_WEEK_DATE);       System.out.println("Formatted date = "+str);    } }OutputDateTime = 2019-09-09T10:20 Formatted date = 2019-W37-1

At first, set the date:LocalDateTime dateTime = LocalDateTime.of(2019, Month.JULY, 9, 10, 20);Now, format the datetime as ISO_DATE_TIME format:String str = dateTime.format(DateTimeFormatter.ISO_DATE_TIME);Exampleimport java.time.LocalDateTime; import java.time.Month; import java.time.format.DateTimeFormatter; public class Demo {    public static void main(String[] args) {       LocalDateTime dateTime = LocalDateTime.of(2019, Month.JULY, 9, 10, 20);       System.out.println("DateTime = "+dateTime);       String str = dateTime.format(DateTimeFormatter.ISO_DATE_TIME);       System.out.println("Formatted date = "+str);    } }OutputDateTime = 2019-07-09T10:20 Formatted date = 2019-07-09T10:20:00

To format and display datetime, you need to use DateTimeFormatter and use the pattern as:DateTimeFormatter dtFormat = DateTimeFormatter.ofPattern("MMM dd yyyy hh:mm a z");Above, the z is the timezone:MMM dd yyyy hh:mm a zNow, use the following for zone:ZonedDateTime dateTime = ZonedDateTime.now();Exampleimport java.time.ZonedDateTime; import java.time.format.DateTimeFormatter; public class Demo {    public static void main(String[] argv) {       DateTimeFormatter dtFormat = DateTimeFormatter.ofPattern("MMM dd yyyy hh:mm a z");       ZonedDateTime dateTime = ZonedDateTime.now();       String res = dateTime.format(dtFormat);       System.out.printf("Date = %s %n", res);    } }OutputDate = Apr 14 2019 01:35 PM IST

To format and display datetime, you need to use DateTimeFormatter. The format style is MEDIUM and SHORT:DateTimeFormatter formatter = DateTimeFormatter .ofLocalizedDateTime(FormatStyle.MEDIUM, FormatStyle.SHORT);Display the formatted date:formatter.format(LocalDateTime.now()Exampleimport java.time.LocalDateTime; import java.time.format.DateTimeFormatter; import java.time.format.FormatStyle; public class Demo {    public static void main(String[] args) {       DateTimeFormatter formatter = DateTimeFormatter .ofLocalizedDateTime(FormatStyle.MEDIUM, FormatStyle.SHORT);       System.out.println("Formatted Date = "+formatter.format(LocalDateTime.now()));    } }OutputFormatted Date = Apr 19, 2019, 1:27 PM

Following is our file:Path p = Paths.get("E:/input.txt"); FileStore file = Files.getFileStore(p);Now, check for the supported attributes one by one:FileAttributeView = file.supportsFileAttributeView(FileAttributeView.class) PosixFileAttributeView = file.supportsFileAttributeView(PosixFileAttributeView.class) BasicFileAttributeView = file.supportsFileAttributeView(BasicFileAttributeView.class)Exampleimport java.nio.file.FileStore; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.nio.file.attribute.BasicFileAttributeView; import java.nio.file.attribute.FileAttributeView; import java.nio.file.attribute.FileOwnerAttributeView; import java.nio.file.attribute.PosixFileAttributeView; public class Demo {    public static void main(String[] args) throws Exception {       Path p = Paths.get("E:/input.txt");       FileStore file = Files.getFileStore(p);       System.out.println("FileAttributeView = " + file.supportsFileAttributeView(FileAttributeView.class));       System.out.println("PosixFileAttributeView = "+ file.supportsFileAttributeView(PosixFileAttributeView.class));       System.out.println("BasicFileAttributeView = "+ file.supportsFileAttributeView(BasicFileAttributeView.class));       System.out.println("FileOwnerAttributeView supported = "+ file.supportsFileAttributeView(FileOwnerAttributeView.class));   ... Read More

Let’s say the following is our list which isn’t read-only:List < Integer > list = new ArrayList < Integer > (); list.add(10); list.add(20); list.add(30); list.add(40); list.add(50); list.add(20); list.add(40); list.add(50);Convert the above list to Read-only:list = Collections.unmodifiableList(list);On conversion, now you won’t be add or remove elements from the List. Let us see an example:The following program will give an error because we first update the list to read only and then try to remove an element from it, which is not possible now. The reason is we have converted the list to readonly and you cannot add or remove element from ... Read More