单例模式

Singleton.java

import java.util.stream.IntStream;

/**
 * Singleton.
 *
 * @author 刘斌
 * @version 0.0.1
 * @serial 2022-02-15 : base version.
 */
public class Singleton {

    public static void main(String[] args) {
        IntStream.range(0, 10).forEach(i -> {
            System.out.println(Load.getInstance());
            System.out.println(LazyLoad.getInstance());
        });
    }


}

class Load {
    private final static Load LOAD = new Load();

    private Load() {
    }

    public static Load getInstance() {
        return LOAD;
    }

    @Override
    public boolean equals(Object obj) {
        return super.equals(obj);
    }
}

class LazyLoad {

    private volatile static LazyLoad load = null;

    private LazyLoad() {
    }

    public static LazyLoad getInstance() {
        if (load == null) {
            synchronized (LazyLoad.class) {
                if (load == null) {
                    load = new LazyLoad();
                }
            }
        }
        return load;
    }

    @Override
    public boolean equals(Object obj) {
        return super.equals(obj);
    }
}