[SalesForce] Lightning problem with component.find(“”).getElements()

You are hitting a timing issue with init that is by design - you should not use component.getElement() in init because elements are not reliably available in init handlers - you'll want to look into using a custom renderer afterRender method which gets called at a point where you are guaranteed to have actual DOM elements available and was designed for exactly this ind of scenario.

https://developer.salesforce.com/docs/atlas.en-us.lightning.meta/lightning/js_renderers.htm

Here is a working example .app of what I think you are saying is not working for you (NOTE TO MODERATORS: I did not use a comment because they do not provide enough formatting capabilities to handle code etc).

@nevrekar_amey Please provide something similar that showcases the error case you are seeing.

<aura:application>
    <div aura:id="divID" class="blue">Hi</div>
    <lightning:button label="Remove Class" onclick="{!c.removeClass}"/>
</aura:application>

controller:

({
    removeClass : function(component, event, helper) {
        helper.removeClassHelperMethod(component);
    }
})

helper:

({
    removeClassHelperMethod : function(component) {
        var divElement = component.find('divID').getElement(); 
        $A.util.removeClass(divElement, 'blue'); 
    }
})

css:

.THIS.blue {
    background-color: blue;
}

Or an even better approach that does not run the risk of colliding with Lightning's stewardship of the DOM elements its managing on your behalf:

<aura:application>
    <aura:attribute name="class" type="String" default="blue" access="private"/>
    <div aura:id="divID" class="{!v.class}">Hi</div>
    <lightning:button label="Toggle Class" onclick="{!c.toggle}"/>
</aura:application>

({
    toggle : function(component, event, helper) {
        component.set("v.class", component.get("v.class") === "" ? "blue" : "");
    }
})

Even better - this approach is also guaranteed to work in your init scenario too!

<aura:application>
    <aura:attribute name="class" type="String" default="blue" access="private"/>
    <aura:handler name="init" value="{!this}" action="{!c.init}"/>

    <div aura:id="divID" class="{!v.class}">Hi</div>
    <lightning:button label="Toggle Class" onclick="{!c.toggle}"/>
</aura:application>

({
    init : function(component, event, helper) {
        component.set("v.class", "green");
    },

    toggle : function(component, event, helper) {
        component.set("v.class", component.get("v.class") === "" ? "blue" : "");
    }
})

.THIS.blue {
    background-color: blue;
}

.THIS.green {
    background-color: green;
}