I have gone through the Play Billing Library 
<https://developer.android.com/google/play/billing/billing_library_overview>
You must acknowledge all purchases within three days. Failure to properly acknowledge purchases results in those purchases being refunded.
The process is doesn't provide any clarity how to acknowledge purchases.
This is what i tried
Is this the correct way to do it.
Thanks in Advance

```
@Override

 public void onPurchasesUpdated(BillingResult billingResult, @Nullable List<Purchase> purchases) {
        if(billingResult.getResponseCode()== BillingClient.BillingResponseCode.OK&&purchases!=null){
            Toast.makeText(this, "Purchase Successful", Toast.LENGTH_SHORT).show();
            for(Purchase purchase:purchases){
                handlePurchase(purchase);
            }
        }else if(billingResult.getResponseCode()== BillingClient.BillingResponseCode.USER_CANCELED){
            Toast.makeText(this, "Purchase Cancelled", Toast.LENGTH_SHORT).show();
        }else if(billingResult.getResponseCode()== BillingClient.BillingResponseCode.ITEM_ALREADY_OWNED){
            Toast.makeText(this, "Already Purchased", Toast.LENGTH_SHORT).show();
        } else{
            Toast.makeText(this, billingResult.getDebugMessage(), Toast.LENGTH_SHORT).show();
        }

    //in handlePurchase()
 if(!purchase.isAcknowledged())
{ 
          AcknowledgePurchaseParams acknowledgePurchaseParams
                    = AcknowledgePurchaseParams.newBuilder()
                    .setPurchaseToken(purchase.getPurchaseToken())
                    .setDeveloperPayload(purchase.getDeveloperPayload())
                    .build();

            client.acknowledgePurchase(acknowledgePurchaseParams, new AcknowledgePurchaseResponseListener() {
                @Override
                public void onAcknowledgePurchaseResponse(BillingResult billingResult) {
                    if(billingResult.getResponseCode()== BillingClient.BillingResponseCode.OK){
                        Toast.makeText(RemoveAdsActivity.this, "Purchase Acknowledged", Toast.LENGTH_SHORT).show();
                    }
                }
            });
        }

```