Enumeration singleton

Enum class implements thread-safe

Singleton:

Singleton pattern is commonly used design patterns, the role is to ensure that a class has only one instance of it, and to provide their own examples of this instance of the entire system. Thread pool, cache, log object, the dialog object, etc. are often designed in one embodiment, select a single embodiment mode to avoid inconsistent state

Simple implementations may refer to  Singleton

But to achieve this there are still shortcomings: serialization could undermine Singleton, creates a new instance each time you deserialize a serialized object instance

 

You can use enumeration to achieve, as follows

public enum  SingletonEnum {
    INSTANCE;
    private String name;
    public String getName(){
        return name;
    }
    public void setName(String name){
        this.name = name;
    }
}

Use direct SingletonEnum.INSTANCE来access, regardless of the issue serialization and reflection.