<h2 id="singleton-object" class="code-line" dir="auto" data-line="2">Singleton Design Pattern</h2>
<p class="code-line" dir="auto" data-line="2">The Singleton design pattern is a creational design pattern that restricts the instantiation of a class to a single object and provides global access to that instance throughout the application. This pattern ensures that only one instance of a class is created and provides a global point of access to it.</p>
<h2 id="singleton-object" class="code-line" dir="auto" data-line="2">Singleton Object</h2>
<p>Singleton object are the object which are instantiated only once for project (jvm). If we try to get the object then we get same object again and again.</p>
<h3 id="lets-create-singleton-patter-using-java" class="code-line" dir="auto" data-line="7">lets create object using singleton pattern using java</h3>
<p>Lazy way of creating singleton object</p>
<pre class="language-java"><code>class Example{


private static Example ob;

public static Example getExample(){
    if(ob==null){
        ob=new Example();
    }
    return ob;
}


}</code></pre>
<h3 id="calling-the-singleton-object" class="code-line" dir="auto" data-line="27">calling the singleton object</h3>
<pre class="language-java"><code>class Main
{
    public static void main(String args[]){
        Example ob=Example.getExample()
        //using the object

    }
    }
}</code></pre>
<p>Eager way of creating Singleton object</p>
<pre class="language-java"><code>class Example{


private static Example ob=new Example();

public static Example getExample(){
      return ob;
}


}
</code></pre>
<p>Accessing object</p>
<pre class="language-java"><code>class Main
{
    public static void main(String args[]){
        Example ob=Example.getExample()
        //using the object

    }
    }
}</code></pre>
<p><span style="background-color: rgb(248, 202, 198);">note: for multithreaded environment we use syncronized block for creating singleton object.</span></p>
<pre class="language-java"><code>class Example{


private static Example ob;

public static Example getExample(){
    if(ob==null){
      syncronized(Example.class){
        if(ob==null)
        {
              ob=new Example();
        }
      }
    }
    return ob;
}


}

</code></pre>
<h2 id="breaking-singleton-design-pattern" class="code-line" dir="auto" data-line="67">Breaking Singleton Design Pattern</h2>
<h3 id="there-are-three-ways-to-break-singleton-design-pattern--lets-talk-about-the-these-way-and-i-am-also-going-to-tell-you-about-the-solution-of-these-problems" class="code-line" dir="auto" data-line="69">There are three ways to break singleton design pattern . Lets talk about it. I am also going to tell you about the solution of these problems.</h3>
<h2 id="1-using-reflection-api" class="code-line" dir="auto" data-line="71">1. Using Reflection API</h2>
<p class="code-line" dir="auto" data-line="73">With the help of relfection api we can call private constructor&nbsp; and create multiple object by calling private constructor.</p>
<h3 id="lets-see-how-we-can-call-private-constructor" class="code-line" dir="auto" data-line="75">lets see how we can call private constructor</h3>
<pre class="language-java"><code>Constructor&lt;Example&gt; constructor=Example.class.getDeclaredConstructor()

//changing the accessibility to true
constructor.setAccessible(true)

Example example=constructor.newInstance();</code></pre>
<h2 id="solution" class="code-line" dir="auto" data-line="87">solution</h2>
<h3 id="we-can-do-the-soultion-in-two-ways" class="code-line" dir="auto" data-line="89">we can do the soultion in two ways.</h3>
<ol class="code-line" dir="auto" data-line="91">
<li class="code-line" dir="auto" style="font-weight: bold;" data-line="91"><strong>using ENUM</strong></li>
</ol>
<pre class="language-java"><code>public enum Example{
    INSTANCE
}</code></pre>
<ol class="code-line" dir="auto" start="2" data-line="101">
<li class="code-line" dir="auto" style="font-weight: bold;" data-line="101"><strong>check the object in private constructor if the object exists then throw exception to terminate the execution.</strong></li>
</ol>
<pre class="language-java"><code>private Exmaple(){

    if(ob!=null)
    {
        throw new RuntimeExcepiton("you are trying to break singleton pattern")
    }
}
</code></pre>
<h2 id="2-using-deserialization" class="code-line" dir="auto" data-line="118">2. Using Deserialization</h2>
<p class="code-line" dir="auto" data-line="120">when we serialize and deserialize the singleton object then singleton pattern automatically got destroyed and provide us different object.</p>
<pre class="language-java"><code>ObjectOutputStream oos = new ObjectOutputStream(new
        FileOutputStream("abc.ob"));
        oos.writeObject(ob);

        System.out.println("serialization done..");

        ObjectInputStream ois = new ObjectInputStream(new FileInputStream("abc.ob"));
        Example s2 = (Example) ois.readObject();
        System.out.println(s2.hashCode());
</code></pre>
<h3 id="solution-1" class="code-line" dir="auto" data-line="137">solution:</h3>
<p class="code-line" dir="auto" data-line="139">just implement readResolve() method</p>
<pre class="language-java"><code> public Object readResolve() {
        return ob;
    }</code></pre>
<h2 id="3-using-cloning" class="code-line" dir="auto" data-line="148">3. Using cloning</h2>
<p class="code-line" dir="auto" data-line="150">when we clone then also we get different object.</p>
<h2 id="solution-2" class="code-line" dir="auto" data-line="152">solution</h2>
<p class="code-line" dir="auto" data-line="154">just override clone method and return the same instance.</p>
<pre class="language-java"><code> @Override
    public Object clone() throws CloneNotSupportedException {
        return samosa;
    }</code></pre>
<p>Video Link:</p>
<p><strong>Singleton Design Pattern:</strong></p>
<p><iframe style="width: 100%; height: 561px; display: table; margin-left: auto; margin-right: auto;" src="https://www.youtube.com/embed/fs6ZUcF-nuc" width="1785" height="1000" allowfullscreen="allowfullscreen"></iframe></p>
<p><strong>Breaking of Singleton design Pattern:</strong></p>
<p><iframe style="display: table; margin-left: auto; margin-right: auto; width: 100%; height: 562px;" src="https://www.youtube.com/embed/zHWusHi9Nt0" width="1772" height="1000" allowfullscreen="allowfullscreen"></iframe></p>

The Singleton design pattern is a creational design pattern that restricts the instantiation of a class to a single object and provides global access to that instance throughout the application. This pattern ensures that only one instance of a class is created and provides a global point of access to it.

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