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The Standard Edition of Java comes with some annotations predefined. You do not need to define them by yourself and you can use them immediately. They allow the compiler to enable some fundamental checking of methods, classes and code. @Override This annotation applies to a method and says that th...

One use of SharedPreferences is to implement a "Settings" screen in your app, where the user can set their preferences / options. Like this: A PreferenceScreen saves user preferences in SharedPreferences. To create a PreferenceScreen, you need a few things: An XML file to define the av...

Scanner scanner = new Scanner(System.in); //Scanner obj to read System input String inputTaken = new String(); while (true) { String input = scanner.nextLine(); // reading one line of input if (input.matches("\\s+")) // if it matches spaces/tabs, stop reading b...

Scanner scanner = null; try { scanner = new Scanner(new File("Names.txt")); while (scanner.hasNext()) { System.out.println(scanner.nextLine()); } } catch (Exception e) { System.err.println("Exception occurred!"); } finally { if (scanner != nul...

Sometimes the same functionality has to be written for different kinds of inputs. At that time, one can use the same method name with a different set of parameters. Each different set of parameters is known as a method signature. As seen per the example, a single method can have multiple signatures....

Needed imports: import javax.sound.sampled.AudioSystem; import javax.sound.sampled.Clip; This code will create a clip and play it continuously once started: Clip clip = AudioSystem.getClip(); clip.open(AudioSystem.getAudioInputStream(new URL(filename))); clip.start(); clip.loop(Clip.LOOP_CO...

The switch statement is Java's multi-way branch statement. It is used to take the place of long if-else if-else chains, and make them more readable. However, unlike if statements, one may not use inequalities; each value must be concretely defined. There are three critical components to the switch...

Paginations in JavaFX use a callback to get the pages used in the animation. Pagination p = new Pagination(); p.setPageFactory(param -> new Button(param.toString())); This creates an infinite list of buttons numbed 0.. since the zero arg constructor creates an infinite pagination. setPageFac...

Pagination p = new Pagination(10); Timeline fiveSecondsWonder = new Timeline(new KeyFrame(Duration.seconds(5), event -> { int pos = (p.getCurrentPageIndex()+1) % p.getPageCount(); p.setCurrentPageIndex(pos); })); fiveSecondsWonder.setCycleCount(Timeline.INDEFINITE); fiveSecondsWon...

ArrayList<String> images = new ArrayList<>(); images.add("some\\cool\\image"); images.add("some\\other\\cool\\image"); images.add("some\\cooler\\image"); Pagination p = new Pagination(3); p.setPageFactory(n -> new ImageView(images.get(n))); Note...

wait() and notify() work in tandem – when one thread calls wait() on an object, that thread will block until another thread calls notify() or notifyAll() on that same object. (See Also: wait()/notify() ) package com.example.examples.object; import java.util.concurrent.atomic.AtomicBoolean; p...

The Collections class offers two standard static methods to sort a list: sort(List<T> list) applicable to lists where T extends Comparable<? super T>, and sort(List<T> list, Comparator<? super T> c) applicable to lists of any type. Applying the former requires amending...

MIDI files can be played by using several classes from the javax.sound.midi package. A Sequencer performs playback of the MIDI file, and many of its methods can be used to set playback controls such as loop count, tempo, track muting, and others. General playback of MIDI data can be done in this wa...

Java's Reflection API allows the programmer to perform various checks and operations on class fields, methods and annotations during runtime. However, in order for an annotation to be at all visible at runtime, the RetentionPolicy must be changed to RUNTIME, as demonstrated in the example below: @i...

Date date = new Date(); System.out.println(date); // Thu Feb 25 05:03:59 IST 2016 Here this Date object contains the current date and time when this object was created. Calendar calendar = Calendar.getInstance(); calendar.set(90, Calendar.DECEMBER, 11); Date myBirthDate = calendar.getTime(); ...

Calendar, Date, and LocalDate Java SE 8 before, after, compareTo and equals methods //Use of Calendar and Date objects final Date today = new Date(); final Calendar calendar = Calendar.getInstance(); calendar.set(1990, Calendar.NOVEMBER, 1, 0, 0, 0); Date birthdate = calendar.getTime(); ...

format() from SimpleDateFormat class helps to convert a Date object into certain format String object by using the supplied pattern string. Date today = new Date(); SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MMM-yy"); //pattern is specified here System.out.println(date...

parse() from SimpleDateFormat class helps to convert a String pattern into a Date object. DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.SHORT, Locale.US); String dateStr = "02/25/2016"; // input String Date date = dateFormat.parse(dateStr); System.out.println(date.getYe...

Calendar objects can be created by using getInstance() or by using the constructor GregorianCalendar. It's important to notice that months in Calendar are zero based, which means that JANUARY is represented by an int value 0. In order to provide a better code, always use Calendar constants, such as...

add() and roll() can be used to increase/decrease Calendar fields. Calendar calendar = new GregorianCalendar(2016, Calendar.MARCH, 31); // 31 March 2016 The add() method affects all fields, and behaves effectively if one were to add or subtract actual dates from the calendar calendar.add(Calend...