// Example of Singleton Pattern in java //
package com.singletondemo;
class SingletonDB {
public static volatile SingletonDB getInstance;
private SingletonDB() {
if (getInstance != null) {
throw (new RuntimeException("instance access only
createInstance()"));
}
}
public static SingletonDB createInstance() {
if (getInstance == null) {
synchronized (SingletonDB.class) {
if (getInstance == null) {
getInstance = new SingletonDB();
}
}
}
return getInstance;
}
}
public class Main {
public static void main(String[] args) {
SingletonDB db = SingletonDB.createInstance();
System.out.println(db);
}
}
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