I’m trying to figure out the below code. ImageIcone called “non-static method” getImage() according to Java API without any instance variable:
public void paintComponent(Graphics g) {
Image img = new ImageIcon("imgtest.jpg", "description...").getImage();
g.drawImage(img,3,4,this);
}
This
new ImageIcon("imgtest.jpg", "description...")
creates an instance. The getImage() method is invoked on that instance and then all references to that instance are lost. The object can then be garbage collected if it is unreachable.
Remember, all you need to invoke an instance method is an expression that resolves to an object reference. A variable of a reference type is one such expression. A constructor invocation is another such expression. An invocation of a method with a return type of some reference type is also such an expression.
Image has a reference to the ImageIcon it came from? I don't know this API at all.
You don't need an 'instance variable.' You only need an instance, and new ImageIcon("imgtest.jpg", "description...") is the instance.
In your code,you are creating an anonymous object of ImageIcon class by using the code new ImageIcon("imgtest.jpg", "description..."). Since you are not going to use that object in future,that's why you are opting to create an anonymous object.
