diff --git a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
index 2c28536f47..a500bd0cad 100644
--- a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
+++ b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
@@ -1306,12 +1306,14 @@ public abstract class CodedOutputStream extends ByteOutput {
 
     @Override
     public final void write(byte value) throws IOException {
+      int position = this.position;
       try {
         buffer[position++] = value;
       } catch (IndexOutOfBoundsException e) {
         throw new OutOfSpaceException(
             String.format("Pos: %d, limit: %d, len: %d", position, limit, 1), e);
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
@@ -1326,11 +1328,12 @@ public abstract class CodedOutputStream extends ByteOutput {
 
     @Override
     public final void writeUInt32NoTag(int value) throws IOException {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       try {
         while (true) {
           if ((value & ~0x7F) == 0) {
             buffer[position++] = (byte) value;
-            return;
+            break;
           } else {
             buffer[position++] = (byte) ((value | 0x80) & 0xFF);
             value >>>= 7;
@@ -1340,10 +1343,12 @@ public abstract class CodedOutputStream extends ByteOutput {
         throw new OutOfSpaceException(
             String.format("Pos: %d, limit: %d, len: %d", position, limit, 1), e);
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
     public final void writeFixed32NoTag(int value) throws IOException {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       try {
         buffer[position++] = (byte) (value & 0xFF);
         buffer[position++] = (byte) ((value >> 8) & 0xFF);
@@ -1353,15 +1358,17 @@ public abstract class CodedOutputStream extends ByteOutput {
         throw new OutOfSpaceException(
             String.format("Pos: %d, limit: %d, len: %d", position, limit, 1), e);
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
     public final void writeUInt64NoTag(long value) throws IOException {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       if (HAS_UNSAFE_ARRAY_OPERATIONS && spaceLeft() >= MAX_VARINT_SIZE) {
         while (true) {
           if ((value & ~0x7FL) == 0) {
             UnsafeUtil.putByte(buffer, position++, (byte) value);
-            return;
+            break;
           } else {
             UnsafeUtil.putByte(buffer, position++, (byte) (((int) value | 0x80) & 0xFF));
             value >>>= 7;
@@ -1372,7 +1379,7 @@ public abstract class CodedOutputStream extends ByteOutput {
           while (true) {
             if ((value & ~0x7FL) == 0) {
               buffer[position++] = (byte) value;
-              return;
+              break;
             } else {
               buffer[position++] = (byte) (((int) value | 0x80) & 0xFF);
               value >>>= 7;
@@ -1383,10 +1390,12 @@ public abstract class CodedOutputStream extends ByteOutput {
               String.format("Pos: %d, limit: %d, len: %d", position, limit, 1), e);
         }
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
     public final void writeFixed64NoTag(long value) throws IOException {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       try {
         buffer[position++] = (byte) ((int) (value) & 0xFF);
         buffer[position++] = (byte) ((int) (value >> 8) & 0xFF);
@@ -1400,17 +1409,18 @@ public abstract class CodedOutputStream extends ByteOutput {
         throw new OutOfSpaceException(
             String.format("Pos: %d, limit: %d, len: %d", position, limit, 1), e);
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
     public final void write(byte[] value, int offset, int length) throws IOException {
       try {
         System.arraycopy(value, offset, buffer, position, length);
-        position += length;
       } catch (IndexOutOfBoundsException e) {
         throw new OutOfSpaceException(
             String.format("Pos: %d, limit: %d, len: %d", position, limit, length), e);
       }
+      position += length;
     }
 
     @Override
@@ -1688,7 +1698,7 @@ public abstract class CodedOutputStream extends ByteOutput {
         while (true) {
           if ((value & ~0x7F) == 0) {
             buffer.put((byte) value);
-            return;
+            break;
           } else {
             buffer.put((byte) ((value | 0x80) & 0xFF));
             value >>>= 7;
@@ -1714,7 +1724,7 @@ public abstract class CodedOutputStream extends ByteOutput {
         while (true) {
           if ((value & ~0x7FL) == 0) {
             buffer.put((byte) value);
-            return;
+            break;
           } else {
             buffer.put((byte) (((int) value | 0x80) & 0xFF));
             value >>>= 7;
@@ -2014,30 +2024,34 @@ public abstract class CodedOutputStream extends ByteOutput {
 
     @Override
     public void writeUInt32NoTag(int value) throws IOException {
+      long position = this.position;  // Perf: hoist field to register to avoid load/stores.
       if (position <= oneVarintLimit) {
         // Optimization to avoid bounds checks on each iteration.
         while (true) {
           if ((value & ~0x7F) == 0) {
             UnsafeUtil.putByte(position++, (byte) value);
-            return;
+            break;
           } else {
             UnsafeUtil.putByte(position++, (byte) ((value | 0x80) & 0xFF));
             value >>>= 7;
           }
         }
       } else {
-        while (position < limit) {
+        while (true) {
+          if (position >= limit) {
+            throw new OutOfSpaceException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, 1));
+          }
           if ((value & ~0x7F) == 0) {
             UnsafeUtil.putByte(position++, (byte) value);
-            return;
+            break;
           } else {
             UnsafeUtil.putByte(position++, (byte) ((value | 0x80) & 0xFF));
             value >>>= 7;
           }
         }
-        throw new OutOfSpaceException(
-            String.format("Pos: %d, limit: %d, len: %d", position, limit, 1));
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
@@ -2048,12 +2062,13 @@ public abstract class CodedOutputStream extends ByteOutput {
 
     @Override
     public void writeUInt64NoTag(long value) throws IOException {
+      long position = this.position;  // Perf: hoist field to register to avoid load/stores.
       if (position <= oneVarintLimit) {
         // Optimization to avoid bounds checks on each iteration.
         while (true) {
           if ((value & ~0x7FL) == 0) {
             UnsafeUtil.putByte(position++, (byte) value);
-            return;
+            break;
           } else {
             UnsafeUtil.putByte(position++, (byte) (((int) value | 0x80) & 0xFF));
             value >>>= 7;
@@ -2063,7 +2078,7 @@ public abstract class CodedOutputStream extends ByteOutput {
         while (position < limit) {
           if ((value & ~0x7FL) == 0) {
             UnsafeUtil.putByte(position++, (byte) value);
-            return;
+            break;
           } else {
             UnsafeUtil.putByte(position++, (byte) (((int) value | 0x80) & 0xFF));
             value >>>= 7;
@@ -2072,6 +2087,7 @@ public abstract class CodedOutputStream extends ByteOutput {
         throw new OutOfSpaceException(
             String.format("Pos: %d, limit: %d, len: %d", position, limit, 1));
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     @Override
@@ -2228,7 +2244,9 @@ public abstract class CodedOutputStream extends ByteOutput {
      * responsibility of the caller.
      */
     final void buffer(byte value) {
+      int position = this.position;
       buffer[position++] = value;
+      this.position = position;  // Only update position if we stayed within the array bounds.
       totalBytesWritten++;
     }
 
@@ -2258,6 +2276,7 @@ public abstract class CodedOutputStream extends ByteOutput {
      * responsibility of the caller.
      */
     final void bufferUInt32NoTag(int value) {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       if (HAS_UNSAFE_ARRAY_OPERATIONS) {
         final long originalPos = position;
         while (true) {
@@ -2276,7 +2295,7 @@ public abstract class CodedOutputStream extends ByteOutput {
           if ((value & ~0x7F) == 0) {
             buffer[position++] = (byte) value;
             totalBytesWritten++;
-            return;
+            break;
           } else {
             buffer[position++] = (byte) ((value | 0x80) & 0xFF);
             totalBytesWritten++;
@@ -2284,6 +2303,7 @@ public abstract class CodedOutputStream extends ByteOutput {
           }
         }
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     /**
@@ -2291,6 +2311,7 @@ public abstract class CodedOutputStream extends ByteOutput {
      * responsibility of the caller.
      */
     final void bufferUInt64NoTag(long value) {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       if (HAS_UNSAFE_ARRAY_OPERATIONS) {
         final long originalPos = position;
         while (true) {
@@ -2309,7 +2330,7 @@ public abstract class CodedOutputStream extends ByteOutput {
           if ((value & ~0x7FL) == 0) {
             buffer[position++] = (byte) value;
             totalBytesWritten++;
-            return;
+            break;
           } else {
             buffer[position++] = (byte) (((int) value | 0x80) & 0xFF);
             totalBytesWritten++;
@@ -2317,6 +2338,7 @@ public abstract class CodedOutputStream extends ByteOutput {
           }
         }
       }
+      this.position = position;  // Only update position if we stayed within the array bounds.
     }
 
     /**
@@ -2324,10 +2346,12 @@ public abstract class CodedOutputStream extends ByteOutput {
      * responsibility of the caller.
      */
     final void bufferFixed32NoTag(int value) {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       buffer[position++] = (byte) (value & 0xFF);
       buffer[position++] = (byte) ((value >> 8) & 0xFF);
       buffer[position++] = (byte) ((value >> 16) & 0xFF);
       buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      this.position = position;  // Only update position if we stayed within the array bounds.
       totalBytesWritten += FIXED32_SIZE;
     }
 
@@ -2336,6 +2360,7 @@ public abstract class CodedOutputStream extends ByteOutput {
      * responsibility of the caller.
      */
     final void bufferFixed64NoTag(long value) {
+      int position = this.position;  // Perf: hoist field to register to avoid load/stores.
       buffer[position++] = (byte) (value & 0xFF);
       buffer[position++] = (byte) ((value >> 8) & 0xFF);
       buffer[position++] = (byte) ((value >> 16) & 0xFF);
@@ -2344,6 +2369,7 @@ public abstract class CodedOutputStream extends ByteOutput {
       buffer[position++] = (byte) ((int) (value >> 40) & 0xFF);
       buffer[position++] = (byte) ((int) (value >> 48) & 0xFF);
       buffer[position++] = (byte) ((int) (value >> 56) & 0xFF);
+      this.position = position;  // Only update position if we stayed within the array bounds.
       totalBytesWritten += FIXED64_SIZE;
     }
   }