From 059a5b011f8b95225e1e30ae0b86529e984e9c0f Mon Sep 17 00:00:00 2001 From: Mike Skells Date: Tue, 12 May 2026 23:59:48 +0100 Subject: [PATCH 1/6] AVRO-4258 remove some allocations from decoder.getBytes() and Utf8 handling --- .../java/org/apache/avro/Conversions.java | 3 +-- .../apache/avro/file/DataFileReader12.java | 4 +-- .../org/apache/avro/file/DataFileStream.java | 4 +-- .../main/java/org/apache/avro/io/Decoder.java | 25 +++++++++++++++++++ .../org/apache/avro/io/FastReaderBuilder.java | 12 +++------ .../org/apache/avro/io/ResolvingDecoder.java | 4 +-- .../avro/reflect/ReflectDatumReader.java | 7 ++---- .../main/java/org/apache/avro/util/Utf8.java | 7 ++++++ .../org/apache/avro/io/TestBinaryDecoder.java | 21 ++++++++++++++++ .../java/org/apache/avro/util/TestUtf8.java | 15 +++++++++++ 10 files changed, 79 insertions(+), 23 deletions(-) diff --git a/lang/java/avro/src/main/java/org/apache/avro/Conversions.java b/lang/java/avro/src/main/java/org/apache/avro/Conversions.java index 2fa15eb959c..9130c572f03 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/Conversions.java +++ b/lang/java/avro/src/main/java/org/apache/avro/Conversions.java @@ -190,8 +190,7 @@ public BigDecimal fromBytes(final ByteBuffer value, final Schema schema, final L try { BigInteger bg = null; - ByteBuffer buffer = decoder.readBytes(null); - byte[] array = buffer.array(); + byte[] array = decoder.readBytes(); if (array.length > 0) { bg = new BigInteger(array); } diff --git a/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java b/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java index c057a86db73..4b29b3a9efe 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java +++ b/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java @@ -75,9 +75,7 @@ public DataFileReader12(SeekableInput sin, DatumReader reader) throws IOExcep do { for (long i = 0; i < l; i++) { String key = vin.readString(null).toString(); - ByteBuffer value = vin.readBytes(null); - byte[] bb = new byte[value.remaining()]; - value.get(bb); + byte[] bb = vin.readBytes(); meta.put(key, bb); } } while ((l = vin.mapNext()) != 0); diff --git a/lang/java/avro/src/main/java/org/apache/avro/file/DataFileStream.java b/lang/java/avro/src/main/java/org/apache/avro/file/DataFileStream.java index e2e79d8eaed..b9a1470d2f4 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/file/DataFileStream.java +++ b/lang/java/avro/src/main/java/org/apache/avro/file/DataFileStream.java @@ -128,9 +128,7 @@ void initialize(InputStream in, byte[] magic) throws IOException { do { for (long i = 0; i < l; i++) { String key = vin.readString(null).toString(); - ByteBuffer value = vin.readBytes(null); - byte[] bb = new byte[value.remaining()]; - value.get(bb); + byte[] bb = vin.readBytes(); header.meta.put(key, bb); header.metaKeyList.add(key); } diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java index 11fc28d762e..0fce30f08ee 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java @@ -20,6 +20,7 @@ import java.io.IOException; import java.nio.ByteBuffer; +import org.apache.avro.SystemLimitException; import org.apache.avro.util.Utf8; /** @@ -41,6 +42,8 @@ public abstract class Decoder { + private static final byte[] EMPTY_BYTES = new byte[0]; + /** * "Reads" a null value. (Doesn't actually read anything, but advances the state * of the parser if the implementation is stateful.) @@ -126,6 +129,28 @@ public abstract class Decoder { */ public abstract ByteBuffer readBytes(ByteBuffer old) throws IOException; + /** + * Reads a byte-string written by {@link Encoder#writeBytes}. + *

+ * This is useful when you want to avoid the creation of a ByteBuffer, and only want the byte[], e.g.: + * 

+   *     ByteBuffer buffer = decoder.readBytes(null);
+   *     byte[] array = buffer.array();
+   *
+ * + * @throws AvroTypeException If this is a stateful reader and byte-string is not the type of the next value to be + * read + */ + public byte[] readBytes() throws IOException { + int length = SystemLimitException.checkMaxBytesLength(readLong()); + if (length == 0) { + return EMPTY_BYTES; + } + byte[] result = new byte[length]; + readFixed(result); + return result; + } + /** * Discards a byte-string written by {@link Encoder#writeBytes}. * diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/FastReaderBuilder.java b/lang/java/avro/src/main/java/org/apache/avro/io/FastReaderBuilder.java index 7ff80e2a4f5..454f5de8673 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/FastReaderBuilder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/FastReaderBuilder.java @@ -385,18 +385,14 @@ private FieldReader createSimpleStringReader(Schema readerSchema) { private FieldReader createBytesPromotingToStringReader(Schema readerSchema) { String stringProperty = readerSchema.getProp(GenericData.STRING_PROP); if (GenericData.StringType.String.name().equals(stringProperty)) { - return (old, decoder) -> getStringFromByteBuffer(decoder.readBytes(null)); + return (old, decoder) -> new String(decoder.readBytes(), StandardCharsets.UTF_8); } else { - return (old, decoder) -> getUtf8FromByteBuffer(old, decoder.readBytes(null)); + return (old, decoder) -> getUtf8FromByteArray(old, decoder.readBytes()); } } - private String getStringFromByteBuffer(ByteBuffer buffer) { - return new String(buffer.array(), buffer.position(), buffer.remaining(), StandardCharsets.UTF_8); - } - - private Utf8 getUtf8FromByteBuffer(Object old, ByteBuffer buffer) { - return (old instanceof Utf8) ? ((Utf8) old).set(new Utf8(buffer.array())) : new Utf8(buffer.array()); + private Utf8 getUtf8FromByteArray(Object old, byte[] bytes) { + return (old instanceof Utf8) ? ((Utf8) old).set(bytes) : new Utf8(bytes); } private FieldReader createUnionReader(WriterUnion action) throws IOException { diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java index 6bdb16a332c..69e5ab1725f 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java @@ -202,7 +202,7 @@ public double readDouble() throws IOException { public Utf8 readString(Utf8 old) throws IOException { Symbol actual = parser.advance(Symbol.STRING); if (actual == Symbol.BYTES) { - return new Utf8(in.readBytes(null).array()); + return old == null? new Utf8(in.readBytes()) : old.set(in.readBytes()); } else { assert actual == Symbol.STRING; return in.readString(old); @@ -213,7 +213,7 @@ public Utf8 readString(Utf8 old) throws IOException { public String readString() throws IOException { Symbol actual = parser.advance(Symbol.STRING); if (actual == Symbol.BYTES) { - return new String(in.readBytes(null).array(), StandardCharsets.UTF_8); + return new String(in.readBytes(), StandardCharsets.UTF_8); } else { assert actual == Symbol.STRING; return in.readString(); diff --git a/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java b/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java index 7ba8e4827c6..8d24177b3c4 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java +++ b/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java @@ -244,14 +244,11 @@ protected Object createString(String value) { @Override protected Object readBytes(Object old, Schema s, Decoder in) throws IOException { - ByteBuffer bytes = in.readBytes(null); Class c = ReflectData.getClassProp(s, SpecificData.CLASS_PROP); if (c != null && c.isArray()) { - byte[] result = new byte[bytes.remaining()]; - bytes.get(result); - return result; + return in.readBytes(); } else { - return bytes; + return in.readBytes(null); } } diff --git a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java index a5c4ece29d7..15b045e22fe 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java +++ b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java @@ -132,6 +132,13 @@ public Utf8 set(String string) { return this; } + public Utf8 set(byte[] bytes) { + this.bytes = bytes; + this.length = SystemLimitException.checkMaxStringLength(length);; + this.hash = 0; + return this; + } + public Utf8 set(Utf8 other) { if (this.bytes.length < other.length) { this.bytes = new byte[other.length]; diff --git a/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java b/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java index 491151b849e..571b5959cbf 100644 --- a/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java +++ b/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java @@ -147,6 +147,12 @@ void eofBytes(boolean useDirect) { Assertions.assertThrows(EOFException.class, () -> newDecoderWithNoData(useDirect).readBytes(null)); } + @ParameterizedTest + @ValueSource(booleans = { true, false }) + void eofBytesRaw(boolean useDirect) { + Assertions.assertThrows(EOFException.class, () -> newDecoderWithNoData(useDirect).readBytes()); + } + @ParameterizedTest @ValueSource(booleans = { true, false }) void eofString(boolean useDirect) { @@ -424,6 +430,13 @@ public void testBytesNegativeLength(boolean useDirect) throws IOException { () -> this.newDecoder(useDirect, -1).readBytes(null)); Assertions.assertEquals(ERROR_NEGATIVE, ex.getMessage()); } + @ParameterizedTest + @ValueSource(booleans = { true, false }) + public void testBytesNegativeLengthRaw(boolean useDirect) throws IOException { + Exception ex = Assertions.assertThrows(AvroRuntimeException.class, + () -> this.newDecoder(useDirect, -1).readBytes()); + Assertions.assertEquals(ERROR_NEGATIVE, ex.getMessage()); + } @ParameterizedTest @ValueSource(booleans = { true, false }) @@ -433,6 +446,14 @@ public void testBytesVmMaxSize(boolean useDirect) throws IOException { Assertions.assertEquals(ERROR_VM_LIMIT_BYTES, ex.getMessage()); } + @ParameterizedTest + @ValueSource(booleans = { true, false }) + public void testBytesVmMaxSizeRaw(boolean useDirect) throws IOException { + Exception ex = Assertions.assertThrows(UnsupportedOperationException.class, + () -> this.newDecoder(useDirect, MAX_ARRAY_VM_LIMIT + 1).readBytes()); + Assertions.assertEquals(ERROR_VM_LIMIT_BYTES, ex.getMessage()); + } + @ParameterizedTest @ValueSource(booleans = { true, false }) public void testBytesMaxCustom(boolean useDirect) throws IOException { diff --git a/lang/java/avro/src/test/java/org/apache/avro/util/TestUtf8.java b/lang/java/avro/src/test/java/org/apache/avro/util/TestUtf8.java index 3e36d9a0214..f77042609cd 100644 --- a/lang/java/avro/src/test/java/org/apache/avro/util/TestUtf8.java +++ b/lang/java/avro/src/test/java/org/apache/avro/util/TestUtf8.java @@ -27,6 +27,7 @@ import java.io.ObjectInputStream; import java.io.ObjectOutputStream; import java.nio.charset.StandardCharsets; +import java.util.Arrays; import org.apache.avro.SystemLimitException; import org.apache.avro.TestSystemLimitException; @@ -97,6 +98,20 @@ void hashCodeReused() { assertEquals(127791473, u.hashCode()); u.setByteLength(4); assertEquals(4122302, u.hashCode()); + + u.set(getTrimmedBytes(new Utf8("zz"))); + assertEquals(4865, u.hashCode()); + u.setByteLength(1); + assertEquals(153, u.hashCode()); + + u.set(getTrimmedBytes(new Utf8("hello"))); + assertEquals(127791473, u.hashCode()); + u.setByteLength(4); + assertEquals(4122302, u.hashCode()); + } + + private byte[] getTrimmedBytes(Utf8 utf8) { + return Arrays.copyOf(utf8.getBytes(), utf8.getByteLength()); } /** From ed5e11540b2c3dc6d41fca2b23fbdc8913a1a7f0 Mon Sep 17 00:00:00 2001 From: Oscar WvH-K Date: Mon, 1 Jun 2026 10:54:01 +0200 Subject: [PATCH 2/6] AVRO-4258: Run spotless:apply --- .../src/main/java/org/apache/avro/io/Decoder.java | 12 +++++++----- .../java/org/apache/avro/io/ResolvingDecoder.java | 2 +- .../src/main/java/org/apache/avro/util/Utf8.java | 3 ++- .../java/org/apache/avro/io/TestBinaryDecoder.java | 1 + 4 files changed, 11 insertions(+), 7 deletions(-) diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java index 0fce30f08ee..a3f1de84f30 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java @@ -132,14 +132,16 @@ public abstract class Decoder { /** * Reads a byte-string written by {@link Encoder#writeBytes}. *

- * This is useful when you want to avoid the creation of a ByteBuffer, and only want the byte[], e.g.: + * This is useful when you want to avoid the creation of a ByteBuffer, and only + * want the byte[], e.g.: + * * 

-   *     ByteBuffer buffer = decoder.readBytes(null);
-   *     byte[] array = buffer.array();
+   * ByteBuffer buffer = decoder.readBytes(null);
+   * byte[] array = buffer.array();
    *
* - * @throws AvroTypeException If this is a stateful reader and byte-string is not the type of the next value to be - * read + * @throws AvroTypeException If this is a stateful reader and byte-string is not + * the type of the next value to be read */ public byte[] readBytes() throws IOException { int length = SystemLimitException.checkMaxBytesLength(readLong()); diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java index 69e5ab1725f..b1445639d18 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java @@ -202,7 +202,7 @@ public double readDouble() throws IOException { public Utf8 readString(Utf8 old) throws IOException { Symbol actual = parser.advance(Symbol.STRING); if (actual == Symbol.BYTES) { - return old == null? new Utf8(in.readBytes()) : old.set(in.readBytes()); + return old == null ? new Utf8(in.readBytes()) : old.set(in.readBytes()); } else { assert actual == Symbol.STRING; return in.readString(old); diff --git a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java index 15b045e22fe..3d92906b324 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java +++ b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java @@ -134,7 +134,8 @@ public Utf8 set(String string) { public Utf8 set(byte[] bytes) { this.bytes = bytes; - this.length = SystemLimitException.checkMaxStringLength(length);; + this.length = SystemLimitException.checkMaxStringLength(length); + ; this.hash = 0; return this; } diff --git a/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java b/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java index 571b5959cbf..06d67a74090 100644 --- a/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java +++ b/lang/java/avro/src/test/java/org/apache/avro/io/TestBinaryDecoder.java @@ -430,6 +430,7 @@ public void testBytesNegativeLength(boolean useDirect) throws IOException { () -> this.newDecoder(useDirect, -1).readBytes(null)); Assertions.assertEquals(ERROR_NEGATIVE, ex.getMessage()); } + @ParameterizedTest @ValueSource(booleans = { true, false }) public void testBytesNegativeLengthRaw(boolean useDirect) throws IOException { From 2d638f7d9d96aa0ca3e5fb6ae613668782b1b9aa Mon Sep 17 00:00:00 2001 From: Oscar WvH-K Date: Mon, 1 Jun 2026 13:44:49 +0200 Subject: [PATCH 3/6] AVRO-4258: Cleanup code --- .../src/main/java/org/apache/avro/file/DataFileReader12.java | 1 - .../main/java/org/apache/avro/reflect/ReflectDatumReader.java | 3 +-- 2 files changed, 1 insertion(+), 3 deletions(-) diff --git a/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java b/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java index 213f3d5072d..489ea6da865 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java +++ b/lang/java/avro/src/main/java/org/apache/avro/file/DataFileReader12.java @@ -19,7 +19,6 @@ import java.io.IOException; import java.io.Closeable; -import java.nio.ByteBuffer; import java.nio.charset.StandardCharsets; import java.util.Arrays; import java.util.HashMap; diff --git a/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java b/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java index 8d24177b3c4..898f3f4a131 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java +++ b/lang/java/avro/src/main/java/org/apache/avro/reflect/ReflectDatumReader.java @@ -19,7 +19,6 @@ import java.io.IOException; import java.lang.reflect.Array; -import java.nio.ByteBuffer; import java.util.ArrayList; import java.util.HashSet; import java.util.HashMap; @@ -132,11 +131,11 @@ protected void addToArray(Object array, long pos, Object e) { throw new AvroRuntimeException("reflectDatumReader does not use addToArray"); } - @Override /** * Called to read an array instance. May be overridden for alternate array * representations. */ + @Override protected Object readArray(Object old, Schema expected, ResolvingDecoder in) throws IOException { Schema expectedType = expected.getElementType(); long l = in.readArrayStart(); From e5ef7b232492709a0f7e261db369015368edb5da Mon Sep 17 00:00:00 2001 From: Oscar WvH-K Date: Mon, 1 Jun 2026 13:45:29 +0200 Subject: [PATCH 4/6] AVRO-4258: Set length with byte array --- lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java index 3d92906b324..6d523209e1b 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java +++ b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java @@ -134,8 +134,7 @@ public Utf8 set(String string) { public Utf8 set(byte[] bytes) { this.bytes = bytes; - this.length = SystemLimitException.checkMaxStringLength(length); - ; + this.length = SystemLimitException.checkMaxStringLength(bytes.length); this.hash = 0; return this; } From bf69352d9617a488ec8c41ec53249c08b50f7da1 Mon Sep 17 00:00:00 2001 From: Oscar WvH-K Date: Mon, 1 Jun 2026 13:46:46 +0200 Subject: [PATCH 5/6] AVRO-4258: Push `readBytes()` implementation down Now colocated with `readBytes(ByteBuffer)` and `skipBytes()` implementations. --- .../java/org/apache/avro/io/BinaryDecoder.java | 8 ++++++++ .../main/java/org/apache/avro/io/Decoder.java | 16 +++------------- .../java/org/apache/avro/io/JsonDecoder.java | 12 ++++++++++++ .../org/apache/avro/io/ResolvingDecoder.java | 12 ++++++++++++ .../org/apache/avro/io/ValidatingDecoder.java | 8 +++++++- 5 files changed, 42 insertions(+), 14 deletions(-) diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java index 77fc8490764..f1993e03b86 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java @@ -334,6 +334,14 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException { return result; } + @Override + public byte[] readBytes() throws IOException { + int length = SystemLimitException.checkMaxBytesLength(readLong()); + final byte[] result = new byte[length]; + doReadBytes(result, 0, length); + return result; + } + @Override public void skipBytes() throws IOException { doSkipBytes(readLong()); diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java index 1ce0d77a3e8..860a9c03712 100644 --- a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java +++ b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java @@ -20,7 +20,7 @@ import java.io.IOException; import java.nio.ByteBuffer; -import org.apache.avro.SystemLimitException; +import org.apache.avro.AvroTypeException; import org.apache.avro.util.Utf8; /** @@ -42,8 +42,6 @@ public abstract class Decoder { - private static final byte[] EMPTY_BYTES = new byte[0]; - /** * "Reads" a null value. (Doesn't actually read anything, but advances the state * of the parser if the implementation is stateful.) @@ -134,7 +132,7 @@ public abstract class Decoder { *

* This is useful when you want to avoid the creation of a ByteBuffer, and only * want the byte[], e.g.: - * + * * 

    * ByteBuffer buffer = decoder.readBytes(null);
    * byte[] array = buffer.array();
@@ -143,15 +141,7 @@ public abstract class Decoder {
    * @throws AvroTypeException If this is a stateful reader and byte-string is not
    *                           the type of the next value to be read
    */
-  public byte[] readBytes() throws IOException {
-    int length = SystemLimitException.checkMaxBytesLength(readLong());
-    if (length == 0) {
-      return EMPTY_BYTES;
-    }
-    byte[] result = new byte[length];
-    readFixed(result);
-    return result;
-  }
+  public abstract byte[] readBytes() throws IOException;
 
   /**
    * Discards a byte-string written by {@link Encoder#writeBytes}.
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
index 1876f87aaac..84ac344f30e 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
@@ -311,6 +311,18 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     }
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    advance(Symbol.BYTES);
+    if (in.getCurrentToken() == JsonToken.VALUE_STRING) {
+      byte[] result = readByteArray();
+      in.nextToken();
+      return result;
+    } else {
+      throw error("bytes");
+    }
+  }
+
   private byte[] readByteArray() throws IOException {
     return in.getText().getBytes(StandardCharsets.ISO_8859_1);
   }
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java
index b1445639d18..43a943c19b4 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java
@@ -243,6 +243,18 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     }
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    Symbol actual = parser.advance(Symbol.BYTES);
+    if (actual == Symbol.STRING) {
+      Utf8 s = in.readString(null);
+      return s.getBytes(); // readString(null) allocated an exactly fitting byte[]
+    } else {
+      assert actual == Symbol.BYTES;
+      return in.readBytes();
+    }
+  }
+
   @Override
   public void skipBytes() throws IOException {
     Symbol actual = parser.advance(Symbol.BYTES);
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java
index 26f79a16ff2..18e72f7e09a 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java
@@ -36,7 +36,7 @@
  * and configure.
  * 

  * ValidatingDecoder is not thread-safe.
- * 
+ *
  * @see Decoder
  * @see DecoderFactory
  */
@@ -124,6 +124,12 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     return in.readBytes(old);
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    parser.advance(Symbol.BYTES);
+    return in.readBytes();
+  }
+
   @Override
   public void skipBytes() throws IOException {
     parser.advance(Symbol.BYTES);

From 2b76d230a4b6c64fe7d9d457b75c2e0ae0c009d7 Mon Sep 17 00:00:00 2001
From: Mike Skells 
Date: Mon, 1 Jun 2026 14:16:36 +0100
Subject: [PATCH 6/6] AVRO-4258 move the implementation to child classes reset
 utf8 string

---
 .../java/org/apache/avro/io/BinaryDecoder.java    | 12 ++++++++++++
 .../src/main/java/org/apache/avro/io/Decoder.java | 15 +++------------
 .../org/apache/avro/io/DirectBinaryDecoder.java   | 15 +++++++++++++++
 .../main/java/org/apache/avro/io/JsonDecoder.java | 12 ++++++++++++
 .../java/org/apache/avro/io/ResolvingDecoder.java | 12 ++++++++++++
 .../org/apache/avro/io/ValidatingDecoder.java     |  8 +++++++-
 .../src/main/java/org/apache/avro/util/Utf8.java  |  4 ++--
 7 files changed, 63 insertions(+), 15 deletions(-)

diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java
index 77fc8490764..7964ce3833d 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/BinaryDecoder.java
@@ -334,6 +334,18 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     return result;
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    int length = SystemLimitException.checkMaxBytesLength(readLong());
+    ensureAvailableBytes(length);
+    if (length == 0) {
+      return EMPTY_BYTES;
+    }
+    byte[] result = new byte[length];
+    doReadBytes(result, 0, result.length);
+    return result;
+  }
+
   @Override
   public void skipBytes() throws IOException {
     doSkipBytes(readLong());
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java
index 1ce0d77a3e8..3e2a945e154 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/Decoder.java
@@ -20,7 +20,6 @@
 import java.io.IOException;
 import java.nio.ByteBuffer;
 
-import org.apache.avro.SystemLimitException;
 import org.apache.avro.util.Utf8;
 
 /**
@@ -42,7 +41,7 @@
 
 public abstract class Decoder {
 
-  private static final byte[] EMPTY_BYTES = new byte[0];
+  protected static final byte[] EMPTY_BYTES = new byte[0];
 
   /**
    * "Reads" a null value. (Doesn't actually read anything, but advances the state
@@ -134,7 +133,7 @@ public abstract class Decoder {
    * 

    * This is useful when you want to avoid the creation of a ByteBuffer, and only
    * want the byte[], e.g.:
-   * 
+   *
    * 
    * ByteBuffer buffer = decoder.readBytes(null);
    * byte[] array = buffer.array();
@@ -143,15 +142,7 @@ public abstract class Decoder {
    * @throws AvroTypeException If this is a stateful reader and byte-string is not
    *                           the type of the next value to be read
    */
-  public byte[] readBytes() throws IOException {
-    int length = SystemLimitException.checkMaxBytesLength(readLong());
-    if (length == 0) {
-      return EMPTY_BYTES;
-    }
-    byte[] result = new byte[length];
-    readFixed(result);
-    return result;
-  }
+  public abstract byte[] readBytes() throws IOException;
 
   /**
    * Discards a byte-string written by {@link Encoder#writeBytes}.
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/DirectBinaryDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/DirectBinaryDecoder.java
index ac251550da2..eafec328c82 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/DirectBinaryDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/DirectBinaryDecoder.java
@@ -51,6 +51,15 @@ public ByteBuffer read(ByteBuffer old, int length) throws IOException {
       result.limit(length);
       return result;
     }
+
+    public byte[] read(int length) throws IOException {
+      if (length == 0) {
+        return EMPTY_BYTES;
+      }
+      final byte[] result = new byte[length];
+      doReadBytes(result, 0, length);
+      return result;
+    }
   }
 
   private class ReuseByteReader extends ByteReader {
@@ -159,6 +168,12 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     return byteReader.read(old, SystemLimitException.checkMaxBytesLength(length));
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    long length = readLong();
+    return byteReader.read(SystemLimitException.checkMaxBytesLength(length));
+  }
+
   @Override
   protected void doSkipBytes(long length) throws IOException {
     while (length > 0) {
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
index 1876f87aaac..84ac344f30e 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
@@ -311,6 +311,18 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     }
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    advance(Symbol.BYTES);
+    if (in.getCurrentToken() == JsonToken.VALUE_STRING) {
+      byte[] result = readByteArray();
+      in.nextToken();
+      return result;
+    } else {
+      throw error("bytes");
+    }
+  }
+
   private byte[] readByteArray() throws IOException {
     return in.getText().getBytes(StandardCharsets.ISO_8859_1);
   }
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java
index b1445639d18..f13d8006993 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/ResolvingDecoder.java
@@ -243,6 +243,18 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     }
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    Symbol actual = parser.advance(Symbol.BYTES);
+    if (actual == Symbol.STRING) {
+      Utf8 s = in.readString(null);
+      return s.getBytes();
+    } else {
+      assert actual == Symbol.BYTES;
+      return in.readBytes();
+    }
+  }
+
   @Override
   public void skipBytes() throws IOException {
     Symbol actual = parser.advance(Symbol.BYTES);
diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java
index 26f79a16ff2..18e72f7e09a 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/ValidatingDecoder.java
@@ -36,7 +36,7 @@
  * and configure.
  * 

  * ValidatingDecoder is not thread-safe.
- * 
+ *
  * @see Decoder
  * @see DecoderFactory
  */
@@ -124,6 +124,12 @@ public ByteBuffer readBytes(ByteBuffer old) throws IOException {
     return in.readBytes(old);
   }
 
+  @Override
+  public byte[] readBytes() throws IOException {
+    parser.advance(Symbol.BYTES);
+    return in.readBytes();
+  }
+
   @Override
   public void skipBytes() throws IOException {
     parser.advance(Symbol.BYTES);
diff --git a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java
index 3d92906b324..8400fa26c97 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/util/Utf8.java
@@ -134,8 +134,8 @@ public Utf8 set(String string) {
 
   public Utf8 set(byte[] bytes) {
     this.bytes = bytes;
-    this.length = SystemLimitException.checkMaxStringLength(length);
-    ;
+    this.length = SystemLimitException.checkMaxStringLength(bytes.length);
+    this.string = null;
     this.hash = 0;
     return this;
   }