Android Question How can i convert strings into json

Dim Subscriptiondetails As Map
        Subscriptiondetails.Initialize
    
        Subscriptiondetails.put("username","5")
        Subscriptiondetails.put("password", "ty3")
        Subscriptiondetails.put("api","depositmobilemoney")
        Subscriptiondetails.put("msisdn",Phones.Text)
        Subscriptiondetails.put("amount",10000)
        Subscriptiondetails.put("narration","Subscription")
        Subscriptiondetails.put("reference","sbscr")
        Subscriptiondetails.put("status_notification_url")