[Demonstration 1]

[Buggy Method]
@Test
public void testReset() {
    IncompleteKey key = keyFactory.projectId("ds1").namespace("ns1").ancestors(PathElement.of("p", 1)).build();
    assertEquals("k", key.kind());
    assertEquals("ds1", key.projectId());
    assertEquals("ns1", key.namespace());
    assertEquals(1, key.ancestors().size());
    keyFactory.reset();
    try {
        keyFactory.newKey(1);
    } catch (NullPointerException ex) {
        assertEquals("kind must not be null", ex.getMessage());
    }
    keyFactory.kind("k1");
    key = keyFactory.newKey();
    assertEquals("k1", key.kind());
    assertEquals(PROJECT_ID, key.projectId());
    assertNull(key.namespace());
    assertTrue(key.ancestors().isEmpty());
    keyFactory = new KeyFactory(PROJECT_ID, "ns1").kind("k");
    key = keyFactory.newKey();
    assertEquals(PROJECT_ID, key.projectId());
    assertEquals("ns1", key.namespace());
    key = keyFactory.projectId("bla1").namespace("bla2").build();
    assertEquals("bla1", key.projectId());
    assertEquals("bla2", key.namespace());
    keyFactory.reset().kind("kind");
    key = keyFactory.newKey();
    assertEquals(PROJECT_ID, key.projectId());
    assertEquals("ns1", key.namespace());
    assertEquals("kind", key.kind());
}

[Buggy Hunk]
assertNull(key.namespace());

[Patch]
assertEquals(0, key.namespace().length());

[Demonstration 2]

[Buggy Method]
public static Result service(String ownerName, String projectName, String service, boolean isAdvertise) throws IOException, UnsupportedOperationException, ServletException {
    if (!isSupportedService(service)) {
        return forbidden(String.format("Unsupported service: '%s'", service));
    }
    Project project = Project.findByOwnerAndProjectName(ownerName, projectName);
    if (project == null) {
        return notFound();
    }
    models.User user = UserApp.currentUser();
    if (!isAllowed(project, service)) {
        if (user.isAnonymous()) {
            return BasicAuthAction.unauthorized(response());
        } else {
            // If you want the Git client showing your custom message to
            // the user, the Content-Type should be exact "text/plain"
            // without any parameter. For more details, see the code at
            // https://github.com/git/git/commit/426e70d4a11ce3b4f70636d57c6a0ab16ae08a00#diff-eea0ad565ec5903a11b6023755d491cfR154
            response().setHeader("Content-Type", "text/plain");
            return forbidden(String.format("'%s' has no permission to '%s/%s'.", user.name, ownerName, projectName));
        }
    }
    if (isAdvertise) {
        return ok(RepositoryService.gitAdvertise(project, service, response()));
    } else {
        if (request().body().isMaxSizeExceeded()) {
            return status(REQUEST_ENTITY_TOO_LARGE);
        } else {
            user.visits(project);
            return ok(RepositoryService.gitRpc(project, service, request(), response()));
        }
    }
}

[Buggy Hunk]
user.name, ownerName, projectName));

[Patch]
user.loginId, ownerName, projectName));

[Demonstration 3]

[Buggy Method]
public static void main(String[] args) throws SQLException {
    Connection conn = DriverManager.getConnection("jdbc:h2:./main");
    () -> {
    }.start();
    Statement stmt = conn.createStatement();
    stmt.execute("CREATE TABLE id IDENTITY, username VARCHAR, address VARCHAR, email VARCHAR");
}

[Buggy Hunk]
().start();

[Patch]
Server.createWebServer().start();