activity_main.xmlMainActivity.java
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:orientation="vertical"
    tools:context="com.codinginflow.futuredateexample.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="getDate"
        android:text="Get date" />

    <TextView
        android:id="@+id/text_view_date"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Today: \nFuture:"
        android:textSize="16sp" />

</LinearLayout>

package com.codinginflow.futuredateexample;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

import java.util.Calendar;
import java.util.Date;

public class MainActivity extends AppCompatActivity {
    private TextView textViewDate;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        textViewDate = findViewById(R.id.text_view_date);
    }

    public void getDate(View v) {
        Calendar c = Calendar.getInstance();
        Date today = c.getTime();

        c.add(Calendar.DATE, 3);
        c.add(Calendar.MONTH, 1);
        c.add(Calendar.YEAR, 1);
        Date future = c.getTime();

        textViewDate.setText("Today: " + today + "\n" + "Future: " + future);
    }
}