Java

The java.lang.Math package is very powerful. Understand more methods in this package that are related to the Euler’s number named e. public class MathMethods{ public static void main(String args[]) { MathMethods mathMethods = new MathMethods(); mathMethods.proceed(); } private void proceed() { //The methid Math.exp returns e^x, where x is the argument

For triggering a synchronous GET request we can rely on HTTP Client API as follows: HttpClient client = HttpClient.newHttpClient();HttpRequest request = HttpRequest.newBuilder() .uri(URI.create(“https://reqres.in/api/users/2”)) .build();HttpResponse response = client.send(request, BodyHandlers.ofString());

To avoid null exceptions, we usually validate against null and emptiness as shown: if(object != null && !object.equals(“”)) {} We can simplify this as below: if(!””.equals(object)){}

The following code shows you how to compute the n Fibonacci number recursively: int fibonacci(int k) { if (k return k; } return fibonacci(k – 2) + fibonacci(k – 1);}

Automation of tasks is a good concept. Consider the example below in which you create a task and schedule it at your convenience to execute the needed actions. There are other types of scheduling as well. Explore them to know more. import java.util.Timer;import java.util.TimerTask;public class TaskScheduling{ public static void main(String

Java arrays are not resizable. But we can work around this constraint with the following trick. int[] newArr = Arrays.copyOf(arr, arr.length + 1);

You can terminate the Java runtime that you are in programmatically. The Java Runtime class provides a method halt(argument) to support this. Of course, caution is advised when using this method to terminate an applications. public class TerminatingJavaRuntime{ public static void main(String args[]) { TerminatingJavaRuntime terminatingJavaRuntime = new TerminatingJavaRuntime(); terminatingJavaRuntime.proceed();

With the Java Reflection API, we can isolate the abstract methods from a class via the following snippet of code: List abstractMethods = new ArrayList();Class clazz = Foo.class;Method[] methods = clazz.getDeclaredMethods();for (Method method : methods) { if (Modifier.isAbstract(method.getModifiers())) { abstractMethods.add(method); }}

Knowing the current flush mode can be done as follows: // via EntityManagerentityManager.getFlushMode();// in Hibernate JPA, via Session(entityManager.unwrap(Session.class)).getFlushMode();// starting with Hibernate 5.2(entityManager.unwrap(Session.class)).getHibernateFlushMode();