Mark Files.createTempDir and FileBackedOutputStream as @J2ObjCIncompatible.

While we believe they're secure under iOS (thanks to OS-level protections on the temporary directory), we are looking into reimplementing them atop `java.nio.file` to improve security under other platforms. And if we do so, then we need to add `java.nio.file` to the JRE deps of every J2ObjC user, possibly increasing app size (at least until improvements to J2ObjC land). After discussion with the J2ObjC team, we've settled on hiding the APIs from J2ObjC for now. Inside Google, the APIs already had no J2ObjC users. If you use them outside Google, let us know, and we can make them available there.

RELNOTES=`io`: Marked `Files.createTempDir` and `FileBackedOutputStream` as `@J2ObjCIncompatible`. Contact us if you need to use them under J2ObjC.
PiperOrigin-RevId: 533564397

Author: cpovirk

android/guava/src/com/google/common/io/FileBackedOutputStream.java

@@ -21,6 +21,7 @@
 import com.google.common.annotations.J2ktIncompatible;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.errorprone.annotations.concurrent.GuardedBy;
+import com.google.j2objc.annotations.J2ObjCIncompatible;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
@@ -54,6 +55,7 @@
 @Beta
 @J2ktIncompatible
 @GwtIncompatible
+@J2ObjCIncompatible
 @ElementTypesAreNonnullByDefault
 public final class FileBackedOutputStream extends OutputStream {
   private final int fileThreshold;

android/guava/src/com/google/common/io/Files.java

@@ -34,6 +34,7 @@
 import com.google.common.hash.HashFunction;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.InlineMe;
+import com.google.j2objc.annotations.J2ObjCIncompatible;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.File;
@@ -426,6 +427,7 @@ public static boolean equal(File file1, File file2) throws IOException {
    */
   @Beta
   @Deprecated
+  @J2ObjCIncompatible
   public static File createTempDir() {
     File baseDir = new File(System.getProperty("java.io.tmpdir"));
     @SuppressWarnings("GoodTime") // reading system time without TimeSource

guava/src/com/google/common/io/FileBackedOutputStream.java

@@ -21,6 +21,7 @@
 import com.google.common.annotations.J2ktIncompatible;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.errorprone.annotations.concurrent.GuardedBy;
+import com.google.j2objc.annotations.J2ObjCIncompatible;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
@@ -54,6 +55,7 @@
 @Beta
 @J2ktIncompatible
 @GwtIncompatible
+@J2ObjCIncompatible
 @ElementTypesAreNonnullByDefault
 public final class FileBackedOutputStream extends OutputStream {
   private final int fileThreshold;

guava/src/com/google/common/io/Files.java

@@ -34,6 +34,7 @@
 import com.google.common.hash.HashFunction;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.InlineMe;
+import com.google.j2objc.annotations.J2ObjCIncompatible;
 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.File;
@@ -426,6 +427,7 @@ public static boolean equal(File file1, File file2) throws IOException {
    */
   @Beta
   @Deprecated
+  @J2ObjCIncompatible
   public static File createTempDir() {
     File baseDir = new File(System.getProperty("java.io.tmpdir"));
     @SuppressWarnings("GoodTime") // reading system time without TimeSource