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Dec 4, 2009 · Java 8 introduced CompletableFuture available in package java.util.concurrent.CompletableFuture, can be used to make a asynch call : CompletableFuture.runAsync(() -> { // method call or code to be asynch.
May 11, 2015 · The only time it is really required is when you have a parameter to a method with the same name as a member variable. Personally, I try to always use it to make the scope of the variable/method explicit. For example you could have a static method or an instance method. When reading the code it can be helpful to know which is which.
class Dummy { private void safeMethod() { StackTraceElement[] st = new Exception().getStackTrace(); // If a method was invoked by reflection, the stack trace would be similar // to something like this: /* java.lang.Exception at package1.b.Dummy.safeMethod(SomeClass.java:38) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke ...
Thanks to Java 8 you don't need to do the steps below to pass a function to a method, that's what lambdas are for, see Oracle's Lambda Expression tutorial. The rest of this post describes what we used to have to do in the bad old days in order to implement this functionality.
Feb 26, 2010 · From the docs of the flush method: Flushes the output stream and forces any buffered output bytes to be written out. The general contract of flush is that calling it is an indication that, if any bytes previously written have been buffered by the implementation of the output stream, such bytes should immediately be written to their intended destination.
Mar 19, 2010 · The static method in java and members in java can be accessed without creating the object of the class. The JVM runs the static method first, followed by the creation of class instances. So, if the static method is initialized before the instance creation, then it is not possible to override it.
Sep 27, 2013 · Here are some main key differences between constructor and method in java. Constructors are called at the time of object creation automatically. But methods are not called during the time of object creation automatically. Constructor name must be same as the class name. Method has no such protocol. The constructors can’t have any return type.
Sep 1, 2010 · A basic implementation is already included in java.lang.Object and so because all objects inherit from java.lang.Object it is guaranteed that every object in Java has this method. Overriding the method is always a good idea, especially when it comes to debugging, because debuggers often show objects by the result of the toString() method.
Nov 22, 2019 · The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true). <br/> Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.
Jul 15, 2009 · Use the following (the contains() method is ArrayUtils.in() in this code): ObjectUtils.java. public class ObjectUtils { /** * A null safe method to detect if two objects are equal. * @param object1 * @param object2 * @return true if either both objects are null, or equal, else returns false.
