You’re already creating an instance of the Thread class – you’re just not doing anything with it. You could call start() without even using a local variable: new Thread() { public void run() { System.out.println(“blah”); } }.start(); … but personally I’d normally assign it to a local variable, do anything else you want (e.g. setting … Read more
Note, as per the comment, I’d just like to point out that I too recommend using a real type when you need to pass it around the program like this. Anonymous types should only really be used locally in a single method at a time (in my opinion), but anyway, here’s the rest of my … Read more
Generally, something like this: methodUsingYourClass(new YourClass() { public void uniqueMethod(Type1 parameter1, Type2 parameter2) { // body of function } }); is replaced with methodUsingYourClass((parameter1, parameter2) -> { // body of function }); The types of the parameters can be inferred from usage, but there may be situations where specifying them is useful. This part from … Read more
Those are the .class files that hold the anonymous inner classes. In your example WelcomeApplet.java contains a top-level class (called WelcomeApplet) and an anonymous inner class, which will be stored in WelcomeApplet$1.class. Note that the exact name of the files holding anonymous inner classes is not standardized and might vary. But in practice I’ve yet … Read more
You can never instantiate an interface in java. You can, however, refer to an object that implements an interface by the type of the interface. For example, public interface A { } public class B implements A { } public static void main(String[] args) { A test = new B(); //A test = new A(); … Read more
From JLS 9.8 A functional interface is an interface that has just one abstract method, and thus represents a single function contract. Lambdas require these functional interfaces so are restricted to their single method. Anonymous interfaces still need to be used for implementing multi-method interfaces. addMouseListener(new MouseAdapter() { @Override public void mouseReleased(MouseEvent e) { … … Read more
Anonymous classes must extend or implement something, like any other Java class, even if it’s just java.lang.Object. For example: Runnable r = new Runnable() { public void run() { … } }; Here, r is an object of an anonymous class which implements Runnable. An anonymous class can extend another class using the same syntax: … Read more
An anonymous inner class (AIC) can be used to create a subclass of an abstract class or a concrete class. An AIC can also provide a concrete implementation of an interface, including the addition of state (fields). An instance of an AIC can be referred to using this in its method bodies, so further methods … Read more
Container.this.select();
Yes, by adding an initializer method that returns ‘this’, and immediately calling that method: int myVariable = 1; myButton.addActionListener(new ActionListener() { private int anonVar; public void actionPerformed(ActionEvent e) { // How would one access myVariable here? // It’s now here: System.out.println(“Initialized with value: ” + anonVar); } private ActionListener init(int var){ anonVar = var; return … Read more