Use Locale.ROOT for all of our formatted error messages.

java/core/src/main/java/com/google/protobuf/AllocatedBuffer.java

@@ -10,6 +10,7 @@
 import static com.google.protobuf.Internal.checkNotNull;
 
 import java.nio.ByteBuffer;
+import java.util.Locale;
 
 /**
  * A buffer that was allocated by a {@link BufferAllocator}. For every buffer, it is guaranteed that
@@ -119,7 +120,8 @@ public static AllocatedBuffer wrap(byte[] bytes) {
   public static AllocatedBuffer wrap(final byte[] bytes, final int offset, final int length) {
     if (offset < 0 || length < 0 || (offset + length) > bytes.length) {
       throw new IndexOutOfBoundsException(
-          String.format("bytes.length=%d, offset=%d, length=%d", bytes.length, offset, length));
+          String.format(
+              Locale.ROOT, "bytes.length=%d, offset=%d, length=%d", bytes.length, offset, length));
     }
 
     return wrapNoCheck(bytes, offset, length);

java/core/src/main/java/com/google/protobuf/BinaryWriter.java

@@ -27,6 +27,7 @@
 import java.nio.ByteOrder;
 import java.util.ArrayDeque;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Queue;
 
@@ -1905,7 +1906,12 @@ public void write(byte value) {
     public void write(byte[] value, int offset, int length) {
       if (offset < 0 || offset + length > value.length) {
         throw new ArrayIndexOutOfBoundsException(
-            String.format("value.length=%d, offset=%d, length=%d", value.length, offset, length));
+            String.format(
+                Locale.ROOT,
+                "value.length=%d, offset=%d, length=%d",
+                value.length,
+                offset,
+                length));
       }
       requireSpace(length);
 
@@ -1917,7 +1923,12 @@ public void write(byte[] value, int offset, int length) {
     public void writeLazy(byte[] value, int offset, int length) {
       if (offset < 0 || offset + length > value.length) {
         throw new ArrayIndexOutOfBoundsException(
-            String.format("value.length=%d, offset=%d, length=%d", value.length, offset, length));
+            String.format(
+                Locale.ROOT,
+                "value.length=%d, offset=%d, length=%d",
+                value.length,
+                offset,
+                length));
       }
       if (spaceLeft() < length) {
         // We consider the value to be immutable (likely the internals of a ByteString). Just

java/core/src/main/java/com/google/protobuf/FieldSet.java

@@ -15,6 +15,7 @@
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
 
@@ -1311,8 +1312,9 @@ private void verifyType(final T descriptor, final Object value) {
         }
         throw new IllegalArgumentException(
             String.format(
+                Locale.ROOT,
                 "Wrong object type used with protocol message reflection.\n"
-                + "Field number: %d, field java type: %s, value type: %s\n",
+                    + "Field number: %d, field java type: %s, value type: %s\n",
                 descriptor.getNumber(),
                 descriptor.getLiteType().getJavaType(),
                 value.getClass().getName()));

java/core/src/main/java/com/google/protobuf/RuntimeVersion.java

@@ -88,7 +88,7 @@ private static void validateProtobufGencodeVersionImpl(
     if (domain != DOMAIN) {
       throw new ProtobufRuntimeVersionException(
           String.format(
-              Locale.US,
+              Locale.ROOT,
               "Detected mismatched Protobuf Gencode/Runtime domains when loading %s: gencode %s,"
                   + " runtime %s. Cross-domain usage of Protobuf is not supported.",
               location,
@@ -104,7 +104,7 @@ private static void validateProtobufGencodeVersionImpl(
       }
       logger.warning(
           String.format(
-              Locale.US,
+              Locale.ROOT,
               " Protobuf prelease version %s in use. This is not recommended for "
                   + "production use.\n"
                   + " You can ignore this message if you are deliberately testing a prerelease."

java/core/src/main/java/com/google/protobuf/TextFormatParseInfoTree.java

@@ -12,6 +12,7 @@
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.Map.Entry;
 
@@ -128,8 +129,10 @@ private static <T> T getFromList(List<T> list, int index, FieldDescriptor fieldD
     if (index >= list.size() || index < 0) {
       throw new IllegalArgumentException(
           String.format(
+              Locale.ROOT,
               "Illegal index field: %s, index %d",
-              fieldDescriptor == null ? "<null>" : fieldDescriptor.getName(), index));
+              fieldDescriptor == null ? "<null>" : fieldDescriptor.getName(),
+              index));
     }
     return list.get(index);
   }

java/core/src/main/java/com/google/protobuf/TextFormatParseLocation.java

@@ -8,6 +8,7 @@
 package com.google.protobuf;
 
 import java.util.Arrays;
+import java.util.Locale;
 
 /**
  * A location in the source code.
@@ -32,7 +33,11 @@ static TextFormatParseLocation create(int line, int column) {
     }
     if (line < 0 || column < 0) {
       throw new IllegalArgumentException(
-          String.format("line and column values must be >= 0: line %d, column: %d", line, column));
+          String.format(
+              Locale.ROOT,
+              "line and column values must be >= 0: line %d, column: %d",
+              line,
+              column));
     }
     return new TextFormatParseLocation(line, column);
   }
@@ -55,7 +60,7 @@ public int getColumn() {
 
   @Override
   public String toString() {
-    return String.format("ParseLocation{line=%d, column=%d}", line, column);
+    return String.format(Locale.ROOT, "ParseLocation{line=%d, column=%d}", line, column);
   }
 
   @Override

java/core/src/test/java/com/google/protobuf/IsValidUtf8TestUtil.java

@@ -15,6 +15,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 import java.util.Random;
 
 /**
@@ -291,7 +292,7 @@ private static String toHexString(byte[] b, int len) {
       if (i > 0) {
         s.append(" ");
       }
-      s.append(String.format("%02x", b[i] & 0xFF));
+      s.append(String.format(Locale.ROOT, "%02x", b[i] & 0xFF));
     }
     s.append("\"");
     return s.toString();

java/lite/src/test/java/com/google/protobuf/LiteTest.java

@@ -53,6 +53,7 @@
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.atomic.AtomicBoolean;
 import org.junit.Before;
 import org.junit.Test;

java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java

@@ -16,6 +16,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map.Entry;
 import java.util.SortedMap;
 import java.util.TreeMap;
@@ -245,6 +246,7 @@ private static void merge(
     if (source.getDescriptorForType() != destination.getDescriptorForType()) {
       throw new IllegalArgumentException(
           String.format(
+              Locale.ROOT,
               "source (%s) and destination (%s) descriptor must be equal",
               source.getDescriptorForType().getFullName(),
               destination.getDescriptorForType().getFullName()));

java/util/src/test/java/com/google/protobuf/util/JsonFormatTest.java

@@ -899,7 +899,9 @@ public void testTimestampMergeError() throws Exception {
     final String incorrectTimestampString = "{\"seconds\":1800,\"nanos\":0}";
     try {
       TestTimestamp.Builder builder = TestTimestamp.newBuilder();
-      mergeFromJson(String.format("{\"timestamp_value\": %s}", incorrectTimestampString), builder);
+      mergeFromJson(
+          String.format(Locale.ROOT, "{\"timestamp_value\": %s}", incorrectTimestampString),
+          builder);
       assertWithMessage("expected exception").fail();
     } catch (InvalidProtocolBufferException e) {
       // Exception expected.
@@ -924,7 +926,8 @@ public void testDurationMergeError() throws Exception {
     final String incorrectDurationString = "{\"seconds\":10,\"nanos\":500}";
     try {
       TestDuration.Builder builder = TestDuration.newBuilder();
-      mergeFromJson(String.format("{\"duration_value\": %s}", incorrectDurationString), builder);
+      mergeFromJson(
+          String.format(Locale.ROOT, "{\"duration_value\": %s}", incorrectDurationString), builder);
       assertWithMessage("expected exception").fail();
     } catch (InvalidProtocolBufferException e) {
       // Exception expected.