if (Character.isDigit(hostname.charAt(0))) {
            int i, len, dots;
            char[] data;

            i = dots = 0; /* quick IP address validation */
            len = hostname.length();
            data = hostname.toCharArray();
            while (i < len && Character.isDigit(data[i++])) {
                if (i == len && dots == 3) {
                    // probably an IP address
                    return true;

        if (Character.isDigit(this.calledName.charAt(0))) {
            int i, len, dots;
            char[] data;

            i = dots = 0; /* quick IP address validation */
            len = this.calledName.length();
            data = this.calledName.toCharArray();
            while (i < len && Character.isDigit(data[i++])) {
                if (i == len && dots == 3) {
                    // probably an IP address

            int i, len, dots;
            char[] data;

            i = dots = 0; /* quick IP address validation */
            len = hostname.length();
            data = hostname.toCharArray();
            while (i < len && Character.isDigit(data[i++])) {
                if (i == len && dots == 3) {
                    // probably an IP address
                    return true;

/**
 * Tests for SpnegoConstants interface.
 * Verifies constant values, modifiers, types, and structural properties.
 */
class SpnegoConstantsTest {

    // Simple OID format: numbers separated by dots (at least one dot)
    private static final Pattern OID_PATTERN = Pattern.compile("\\d+(?:\\.\\d+)+");

    @Test
    @DisplayName("Constant values match expected OIDs")
    void constantValues() {

        // Normal extensions should be allowed
        assertEquals("\\share\\file.txt", validator.validatePath("\\share\\file.txt"));
        assertEquals("\\share\\document.docx", validator.validatePath("\\share\\document.docx"));
        assertEquals("\\share\\archive.tar.gz", validator.validatePath("\\share\\archive.tar.gz"));
    }

    @Test
    public void testInternationalCharacters() throws Exception {

Remember how our app/file structure looks like:

<img src="/img/tutorial/bigger-applications/package.drawio.svg">

---

The two dots `..`, like in:

```Python
from ..dependencies import get_token_header
```

mean:

* Starting in the same package that this module (the file `app/routers/items.py`) lives in (the directory `app/routers/`)...

        if (Character.isDigit(calledName.charAt(0))) {
            int i, len, dots;
            char[] data;

            i = dots = 0; /* quick IP address validation */
            len = calledName.length();
            data = calledName.toCharArray();
            while (i < len && Character.isDigit(data[i++])) {
                if (i == len && dots == 3) {
                    // probably an IP address

   */
  private InternetDomainName ancestor(int levels) {
    ImmutableList<String> ancestorParts = parts.subList(levels, parts.size());

    // levels equals the number of dots that are getting clipped away, then add the length of each
    // clipped part to get the length of the leading substring that is being removed.
    int substringFrom = levels;
    for (int i = 0; i < levels; i++) {

/* jcifs smb client library in Java
 * Copyright (C) 2002  "Michael B. Allen" <jcifs at samba dot org>
 *                   "Eric Glass" <jcifs at samba dot org>
 *                   "Jason Pugsley" <jcifs at samba dot org>
 *                   "skeetz" <jcifs at samba dot org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either

/* jcifs smb client library in Java
 * Copyright (C) 2002  "Michael B. Allen" <jcifs at samba dot org>
 *                   "Eric Glass" <jcifs at samba dot org>
 *                   "Jason Pugsley" <jcifs at samba dot org>
 *                   "skeetz" <jcifs at samba dot org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either