为什么有时不必在Java中声明“新”对象？

Question

Apologies for what is probably an easy question. I cannot find anything straight forward to answer this one. In the following code, why am I not required to create a "new" object? What exactly am I assigning sequencer to?

import javax.sound.midi.*;

public class MusicTest1 {

    public void play() {
        Sequencer sequencer = MidiSystem.getSequencer();

        System.out.println("We got a sequencer");
    } // close play

    public static void main(String[] args) {
        MusicTest1 mt = new MusicTest1();
        mt.play();
    }
}

Answer 1

If you are referring to Sequencer sequencer = MidiSystem.getSequencer(); , you are calling a static method of the class MidiSystem that returns an instance of Sequencer . The static method does the new Sequencer() for you.

Answer 2

The function getSequencer makes a new object and returns it. It probably returns the same object if it has already created one. This is called the singleton pattern.