Singleton Pattern

Singleton Pattern: Ensure a class only has one instance and provide a global point of access to it.

Example

ConnectionManager.java

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package com.singletonpattern.example;   public class ConnectionManager {     private static ConnectionManager connectionManager = new ConnectionManager();    private ConnectionManager() {   System.out.println("Database Connection set successfully");  }    public static ConnectionManager getConnectionInstance() {   return connectionManager;  }    }

EntityManger.java

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package com.singletonpattern.example;   public class EntityManger {     public void getItemDetails(ConnectionManager connectionManager){   System.out.println("Now performing  database select operation using connectionManager instance");  } }

ConnectionManagerTestDrive.java

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package com.singletonpattern.example;   public class ConnectionManagerTestDrive {  public static void main(String[] args) {   //Using single instance of Connection Manager   ConnectionManager dbConnection = ConnectionManager.getConnectionInstance();   EntityManger entityManger = new EntityManger();   entityManger.getItemDetails(dbConnection);  } }

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