Gera 15 números aleatórios de 1 a 25

Set<Integer> uniqueNumbers1 = new HashSet<>();
Random random = new Random();
while (uniqueNumbers1.size() < 15) {
    uniqueNumbers1.add(random.nextInt(25) + 1);
}
List<Integer> randomNumbers1 = new ArrayList<>(uniqueNumbers1);

TextView textView1 = (TextView) findViewById(R.id.textview1);
textView1.setText(TextUtils.join(", ", randomNumbers1));

Set<Integer> uniqueNumbers2 = new HashSet<>();
while (uniqueNumbers2.size() < 15) {
    uniqueNumbers2.add(random.nextInt(25) + 1);
}
List<Integer> randomNumbers2 = new ArrayList<>(uniqueNumbers2);

TextView textView2 = (TextView) findViewById(R.id.textview2);
textView2.setText(TextUtils.join(", ", randomNumbers2));

List<Integer> randomNumbers3 = new ArrayList<>(randomNumbers1);
randomNumbers3.retainAll(randomNumbers2);

for (Integer num : randomNumbers3) {
    int start1 = textView1.getText().toString().indexOf(num.toString());
    int end1 = start1 + num.toString().length();
    int start2 = textView2.getText().toString().indexOf(num.toString());
    int end2 = start2 + num.toString().length();

    Spannable spannable1 = new SpannableString(textView1.getText());
    spannable1.setSpan(new ForegroundColorSpan(Color.RED), start1, end1, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    textView1.setText(spannable1);
    Spannable spannable2 = new SpannableString(textView2.getText());
    spannable2.setSpan(new ForegroundColorSpan(Color.RED), start2, end2, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
    textView2.setText(spannable2);
}

TextView textView3 = (TextView) findViewById(R.id.textview3);
String repeatedNumber = "Números repetidos: " + randomNumbers3.size();
textView3.setText(repeatedNumber);