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4847239: (spec) File.createTempFile() should make it clear that it do…
…esn't create the temporary directory

Reviewed-by: naoto, lancea
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Brian Burkhalter committed Jun 25, 2021
1 parent 3fae4b3 commit 68ef21d
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11 changes: 10 additions & 1 deletion src/java.base/share/classes/java/io/
Expand Up @@ -2110,6 +2110,13 @@ static File generateFile(String prefix, String suffix, File dir)
* is invoked, but programmatic changes to this property are not guaranteed
* to have any effect upon the temporary directory used by this method.
* <p> If the {@code directory} argument is not {@code null} and its
* abstract pathname is valid and denotes an existing, writable directory,
* then the file will be created in that directory. Otherwise the file will
* not be created and an {@code IOException} will be thrown. Under no
* circumstances will a directory be created at the location specified by
* the {@code directory} argument.
* @param prefix The prefix string to be used in generating the file's
* name; must be at least three characters long
Expand All @@ -2127,7 +2134,8 @@ static File generateFile(String prefix, String suffix, File dir)
* If the {@code prefix} argument contains fewer than three
* characters
* @throws IOException If a file could not be created
* @throws IOException
* If a file could not be created
* @throws SecurityException
* If a security manager exists and its {@link
Expand All @@ -2149,6 +2157,7 @@ public static File createTempFile(String prefix, String suffix,

File tmpdir = (directory != null) ? directory
: TempDirectory.location();

SecurityManager sm = System.getSecurityManager();
File f;
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105 changes: 105 additions & 0 deletions test/jdk/java/io/File/createTempFile/
@@ -0,0 +1,105 @@
* Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit if you need additional information or have any
* questions.

* @test
* @bug 4847239
* @summary Verify directory parameter behavior in File.createTempFile(String,String,File)

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.attribute.AclEntry;
import java.nio.file.attribute.AclEntryPermission;
import java.nio.file.attribute.AclFileAttributeView;
import java.nio.file.attribute.PosixFileAttributeView;
import java.nio.file.attribute.PosixFilePermission;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class TargetDirectory {
public static void main(String[] args) throws Exception {
// Target directory exists and is writable
Path dir = Path.of("target");
File target = Files.createDirectory(dir).toFile();
File tmp = File.createTempFile("passes", null, target);
if (!Files.exists(tmp.toPath())) {
throw new RuntimeException("Temp file not created");

// Make target directory read-only
if (Files.getFileStore(dir).supportsFileAttributeView("posix")) {
PosixFileAttributeView view =
Files.getFileAttributeView(dir, PosixFileAttributeView.class);
Set<PosixFilePermission> perms = new HashSet<>();
} else if (Files.getFileStore(dir).supportsFileAttributeView("acl")) {
AclFileAttributeView view = Files.getFileAttributeView(dir,
List<AclEntry> entries = new ArrayList<>();
for (AclEntry entry : view.getAcl()) {
Set<AclEntryPermission> perms =
new HashSet<>(entry.permissions());
} else {
throw new RuntimeException("Required attribute view not supported");

// Target directory exists but is read-only
try {
File.createTempFile("readonly", null, target);
throw new RuntimeException("Exception not thrown for read-only target directory");
} catch (IOException expected) {
} finally {

// Target directory does not exist
try {
File.createTempFile("nonexistent", null, new File("void"));
throw new RuntimeException("Exception not thrown for non-existent target directory");
} catch (IOException expected) {

// Target is a file, not a directory
target = Files.createFile(Path.of("file")).toFile();
try {
File.createTempFile("file", null, target);
throw new RuntimeException("Exception not thrown for file target");
} catch (IOException expected) {
} finally {

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