Tutorial by Examples: java

For queries, Realm provides the realmResults.asObservable() method. Observing results is only possible on looper threads (typically the UI thread). For this to work, your configuration must contain the following realmConfiguration = new RealmConfiguration.Builder(context) // ...

A lambda closure is created when a lambda expression references the variables of an enclosing scope (global or local). The rules for doing this are the same as those for inline methods and anonymous classes. Local variables from an enclosing scope that are used within a lambda have to be final. Wit...

To export a you need to fill the report to get the JasperPrint object. Export single JasperPrint (single jrxml) to file // 1. Create exporter instance JRPdfExporter exporter = new JRPdfExporter(); // 2. Set exporter input document exporter.setExporterInput(new SimpleExporterInput(jasperPrint)...

int [] arr = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}; for(int value : arr) { System.out.print(value); System.out.print("\n"); } *Note that the Java foreach is just a for loop with different syntax. Some languages do this and some such as C# use foreach.

var numbers = [1,2,3,4,5]; var squares = numbers.map(function(x) { return x*x; }); // squares is [1,4,9,16,25]

var arr = [1, 2, 3, 4, 5]; var sum = arr.reduce((prev, curr) => prev + curr); console.log(sum); // Output: 15 You can also specify an initial value var arr = [1, 2, 3, 4, 5]; var sum = arr.reduce(function (previousValue, currentValue, currentIndex, array) { return previousValue + cur...

Consider the following naive method for adding two positive numbers using recursion: public static int add(int a, int b) { if (a == 0) { return b; } else { return add(a - 1, b + 1); // TAIL CALL } } This is algorithmically correct, but it has a major problem. ...

Singletons in Java are very similar to C#, being as both languages are object orientated. Below is an example of a singleton class, where only one version of the object can be alive during the program's lifetime (Assuming the program works on one thread) public class SingletonExample { priva...

Formatting a JavaScript date in modern browsers In modern browsers (*), Date.prototype.toLocaleDateString() allows you to define the formatting of a Date in a convenient manner. It requires the following format : dateObj.toLocaleDateString([locales [, options]]) The locales parameter should be...

Simple example Assuming that the "HelloWorld.java" contains the following Java source: public class HelloWorld { public static void main(String[] args) { System.out.println("Hello world!"); } } (For an explanation of the above code, please refer to Gettin...

This is an example of a package-info.java file that binds an XML namespace to a serializable Java class. This should be placed in the same package as the Java classes that should be serialized using the namespace. /** * A package containing serializable classes. */ @XmlSchema ( xmlns = ...

Facade is structural design pattern. It hides the complexities of large system and provides a simple interface to client. Client uses only Facade and it's not worried about inter dependencies of sub-systems. Definition from Gang of Four book: Provide a unified interface to a set of interfaces i...

XSD schema (schema.xsd) The following xml schema (xsd) defines a list of users with attributes name and reputation. <?xml version="1.0"?> <xs:schema version="1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:ns="http://www...

n order to debug a remote Java application, it should be launched with some extra arguments to instruct the JVM to execute it in debug mode. This is done as follows: java -Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=n,address=8000 -jar sampleApp.jar The above command tells the JVM to s...

Javassist is a bytecode instrumentation library that allows you to modify bytecode injecting Java code that will be converted to bytecode by Javassist and added to the instrumented class/method at runtime. Lets write the first transformer that actually take an hypothetical class "com.my.to.be....

Visitor pattern allows you to add new operations or methods to a set of classes without modifying the structure of those classes. This pattern is especially useful when you want to centralise a particular operation on an object without extending the object Or without modifying the object. UML diag...

Lets assume that in your current codebase, there exists MyLogger interface like so: interface MyLogger { void logMessage(String message); void logException(Throwable exception); } Lets say that you've created a few concrete implementations of these, such as MyFileLogger and MyConsol...

For an instance, if the html source code of an html view or element is wrapped by an iframe like this: <iframe src="../images/eightball.gif" name="imgboxName" id="imgboxId"> <p>iframes example</p> <a href="../images/redball.gif" t...

To switch focus to either main document or first frame of the page. You have to use below syntax. driver.switchTo().defaultContent();

You can disable Lint checking from your Java and XML source files. Configuring lint checking in Java To disable Lint checking specifically for a Java class or method in your Android project, add the @SuppressLint annotation to that Java code. Example: @SuppressLint("NewApi") @Override...