Tutorial by Examples: d

If we consider a heterogenous list, wherein the elements of the list have varied but known types, it might be desirable to be able to perform operations on the elements of the list collectively without discarding the elements' type information. The following example implements a mapping operation ov...

Suppose the following generic interface has been declared: public interface MyGenericInterface<T> { public void foo(T t); } Below are listed the possible ways to implement it. Non-generic class implementation with a specific type Choose a specific type to replace the formal type ...

This option disables the fat lock spin code in Java, allowing threads that block trying to acquire a fat lock go to sleep directly. Objects in Java become a lock as soon as any thread enters a synchronized block on that object. All locks are held (that is, stayed locked) until released by the locki...

This option disables the garbage collector strategy changes. Compaction heuristics and nursery size heuristics are not affected by this option. By default, the garbage collection heuristics are enabled. Usage: -XXdisableFatSpin

This option causes a dump file to be generated and allows you to specify the relative size of that file (that is, small, medium, or large). Usage: -XXdumpsize:<size> <size>DescriptionnoneDoes not generate a dump file.smallOn Windows, a small dump file is generated (on Linux a full c...

Reading file using a BufferedInputStream generally faster than FileInputStream because it maintains an internal buffer to store bytes read from the underlying input stream. import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.IOException; public class FileReadin...

Each Java Thread has an interrupt flag, which is initially false. Interrupting a thread, is essentially nothing more than setting that flag to true. The code running on that thread can check the flag on occasion and act upon it. The code can also ignore it completely. But why would each Thread have...

The double tap, like a single tap, also uses the UITapGestureRecognizer. You simply set the numberOfTapsRequired to 2. Swift override func viewDidLoad() { super.viewDidLoad() // Double Tap let doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(handleDoubleTa...

Drag a gesture recognizer from the object library onto your view. Control drag from the gesture in the Document Outline to your View Controller code in order to make an Outlet and an Action. Notes This example comes from this fuller sample project demonstrating gesture recognizers.

//Creates a Random instance with a seed of 12345. Random random = new Random(12345L); //Gets a ThreadLocalRandom instance ThreadLocalRandom tlr = ThreadLocalRandom.current(); //Set the instance's seed. tlr.setSeed(12345L); Using the same seed to generate random numbers will return the sa...

The current release version of Jetty is 9.4. Support is still provided for Jetty 9.2 and 9.3, and maintenance releases are provided for Jetty 7 and Jetty 8 when needed. The most up-to-date distributions can be found on the Jetty Downloads page. It is worth noting that current releases of Jetty requ...

Add below entries in pom.xml. <dependency> <groupId>org.springframework.security</groupId> <artifactId>spring-security-web</artifactId> <version>3.1.0.RELEASE</version> </dependency> <dependency> <groupId>org.springfr...

Bytecode is the set of instructions used by the JVM. To illustrate this let's take this Hello World program. public static void main(String[] args){ System.out.println("Hello World"); } This is what it turns into when compiled into bytecode. public static main([Ljava/lang/String...

Firstly the classes from the jar need to be loaded. We'll use three methods for this process: loadClasses(File) readJar(JarFile, JarEntry, Map) getNode(byte[]) Map<String, ClassNode> loadClasses(File jarFile) throws IOException { Map<String, ClassNode> classes = new HashMap&...

/** * Load a class by from a ClassNode * * @param cn * ClassNode to load * @return */ public static Class<?> load(ClassNode cn) { ClassWriter cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES); return new ClassDefiner(ClassLoader.getSystemClassLoader()).get(cn....

Objects come in their own class, so a simple example would be a car (detailed explanations below): public class Car { //Variables describing the characteristics of an individual car, varies per object private int milesPerGallon; private String name; private String color; ...

When a page is part of a series of articles, for instance, one can use prev and next to point to pages that are coming before and after. <link rel="prev" href="http://stackoverflow.com/documentation/java/topics"> <link rel="next" href="http://stackover...

Preconnect The preconnect relationship is similar to dns-prefetch in that it will resolve the DNS. However, it will also make the TCP handshake, and optional TLS negotiation. This is an experimental feature. <link rel="preconnect" href="URL"> DNS-Prefetch Informs bro...

# Process substitution with paste command is common # To compare the contents of two directories paste <( ls /path/to/directory1 ) <( ls /path/to/directory1 )

To write data to a file using Channel we need to have the following steps: First, we need to get an object of FileOutputStream Acquire FileChannel calling the getChannel() method from the FileOutputStream Create a ByteBuffer and then fill it with data Then we have to call the flip() method of ...