Best of static method and non static method : <p>I have Util classes where i have many methods to be used in all over project.
My question is - considering memory heap, performance what is best to use a static method by class reference or non static method called by object of that class. For example:</p>

<pre><code>public class Utilities {

    private static Utilities utils;

    public static Utilities getInstance() {
        if (utils == null)
            utils = new Utilities();
        return utils;
    }

    public static void someMethod() {

    }

    public void someMethod2() {

    }

}
</code></pre>

<p>and</p>

<pre><code>public static void main(String[] args) {
    Utilities.someMethod();
    Utilities.getInstance().someMethod2();
}
</code></pre>

<p>Which is correct way for my requirement?</p>
