perf(java): optimize scoped meta share mode perf (#1734)

## What does this PR do?

This PR optimizes scoped meta share mode writing perf by about 30%:
- Replace ArrayList by ObjectArray, which can save `clear` cost
- Speed up copy performance when writing classdefs 

## Related issues

#1733 

## Does this PR introduce any user-facing change?

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- [ ] Does this PR introduce any public API change?
- [ ] Does this PR introduce any binary protocol compatibility change?


## Benchmark

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java/fury-core/src/main/java/org/apache/fury/collection/ObjectArray.java

@@ -25,7 +25,8 @@
  * An auto-growing array which avoid checks in {@code ArrayList} and faster for {@code clear}
  * method.
  */
-public final class ObjectArray {
+@SuppressWarnings("unchecked")
+public final class ObjectArray<T> {
   private static final int COPY_THRESHOLD = 128;
   private static final int NIL_ARRAY_SIZE = 1024;
   private static final Object[] NIL_ARRAY = new Object[NIL_ARRAY_SIZE];
@@ -41,7 +42,7 @@ public ObjectArray(int initialCapacity) {
     objects = new Object[initialCapacity];
   }
 
-  public void add(Object element) {
+  public void add(T element) {
     Object[] objects = this.objects;
     int size = this.size++;
     if (objects.length <= size) {
@@ -53,22 +54,22 @@ public void add(Object element) {
     objects[size] = element;
   }
 
-  public void set(int index, Object element) {
+  public void set(int index, T element) {
     objects[index] = element;
   }
 
-  public Object get(int index) {
-    return objects[index];
+  public T get(int index) {
+    return (T) objects[index];
   }
 
   /** Returns tail item or null if no available item in the array. */
-  public Object popOrNull() {
+  public T popOrNull() {
     int size = this.size;
     if (size == 0) {
       return null;
     }
     this.size = --size;
-    return objects[size];
+    return (T) objects[size];
   }
 
   public void clear() {

java/fury-core/src/main/java/org/apache/fury/memory/MemoryBuffer.java

@@ -233,6 +233,14 @@ public boolean isOffHeap() {
     return heapMemory == null;
   }
 
+  /**
+   * Returns <tt>true</tt>, if the memory buffer is backed by heap memory and memory buffer can
+   * write to the whole memory region of underlying byte array.
+   */
+  public boolean isHeapFullyWriteable() {
+    return heapMemory != null && heapOffset == 0;
+  }
+
   /**
    * Get the heap byte array object.
    *

java/fury-core/src/main/java/org/apache/fury/meta/ClassDef.java

@@ -197,7 +197,7 @@ public String toString() {
 
   /** Write class definition to buffer. */
   public void writeClassDef(MemoryBuffer buffer) {
-    buffer.writeBytes(encoded);
+    buffer.writeBytes(encoded, 0, encoded.length);
   }
 
   /** Read class definition from buffer. */

java/fury-core/src/main/java/org/apache/fury/resolver/ClassInfo.java

@@ -48,7 +48,7 @@ public class ClassInfo {
   // class id must be less than Integer.MAX_VALUE/2 since we use bit 0 as class id flag.
   short classId;
   ClassDef classDef;
-  public boolean needToWriteClassDef;
+  boolean needToWriteClassDef;
 
   ClassInfo(
       Class<?> cls,

java/fury-core/src/main/java/org/apache/fury/resolver/ClassResolver.java

@@ -88,6 +88,7 @@
 import org.apache.fury.collection.IdentityMap;
 import org.apache.fury.collection.IdentityObjectIntMap;
 import org.apache.fury.collection.LongMap;
+import org.apache.fury.collection.ObjectArray;
 import org.apache.fury.collection.ObjectMap;
 import org.apache.fury.collection.Tuple2;
 import org.apache.fury.config.CompatibleMode;
@@ -204,7 +205,9 @@ public class ClassResolver {
   private static final float loadFactor = 0.25f;
   private static final float furyMapLoadFactor = 0.25f;
   private static final int estimatedNumRegistered = 150;
-  private static final String META_SHARE_FIELDS_INFO_KEY = "shareFieldsInfo";
+  private static final String SET_META__CONTEXT_MSG =
+      "Meta context must be set before serialization, "
+          + "please set meta context by SerializationContext.setMetaContext";
   private static final ClassInfo NIL_CLASS_INFO =
       new ClassInfo(null, null, null, null, false, null, null, ClassResolver.NO_CLASS_ID);
 
@@ -1285,10 +1288,7 @@ public void writeClassWithMetaShare(MemoryBuffer buffer, ClassInfo classInfo) {
       return;
     }
     MetaContext metaContext = fury.getSerializationContext().getMetaContext();
-    Preconditions.checkNotNull(
-        metaContext,
-        "Meta context must be set before serialization, "
-            + "please set meta context by SerializationContext.setMetaContext");
+    assert metaContext != null : SET_META__CONTEXT_MSG;
     IdentityObjectIntMap<Class<?>> classMap = metaContext.classMap;
     int newId = classMap.size;
     int id = classMap.putOrGet(classInfo.cls, newId);
@@ -1332,19 +1332,16 @@ boolean needToWriteClassDef(Serializer serializer) {
   }
 
   private ClassInfo readClassInfoWithMetaShare(MemoryBuffer buffer, MetaContext metaContext) {
-    Preconditions.checkNotNull(
-        metaContext,
-        "Meta context must be set before serialization,"
-            + " please set meta context by SerializationContext.setMetaContext");
+    assert metaContext != null : SET_META__CONTEXT_MSG;
     int header = buffer.readVarUint32Small14();
     int id = header >>> 1;
     if ((header & 0b1) == 0) {
       return getOrUpdateClassInfo((short) id);
     }
-    List<ClassInfo> readClassInfos = metaContext.readClassInfos;
+    ObjectArray<ClassInfo> readClassInfos = metaContext.readClassInfos;
     ClassInfo classInfo = readClassInfos.get(id);
     if (classInfo == null) {
-      List<ClassDef> readClassDefs = metaContext.readClassDefs;
+      ObjectArray<ClassDef> readClassDefs = metaContext.readClassDefs;
       ClassDef classDef = readClassDefs.get(id);
       Tuple2<ClassDef, ClassInfo> classDefTuple = extRegistry.classIdToDef.get(classDef.getId());
       if (classDefTuple == null || classDefTuple.f1 == null) {
@@ -1433,11 +1430,31 @@ private ClassInfo getMetaSharedClassInfo(ClassDef classDef, Class<?> clz) {
    */
   public void writeClassDefs(MemoryBuffer buffer) {
     MetaContext metaContext = fury.getSerializationContext().getMetaContext();
-    buffer.writeVarUint32Small7(metaContext.writingClassDefs.size());
-    for (ClassDef classDef : metaContext.writingClassDefs) {
-      classDef.writeClassDef(buffer);
+    ObjectArray<ClassDef> writingClassDefs = metaContext.writingClassDefs;
+    final int size = writingClassDefs.size;
+    buffer.writeVarUint32Small7(size);
+    if (buffer.isHeapFullyWriteable()) {
+      writeClassDefs(buffer, writingClassDefs, size);
+    } else {
+      for (int i = 0; i < size; i++) {
+        writingClassDefs.get(i).writeClassDef(buffer);
+      }
+    }
+    metaContext.writingClassDefs.size = 0;
+  }
+
+  private void writeClassDefs(
+      MemoryBuffer buffer, ObjectArray<ClassDef> writingClassDefs, int size) {
+    int writerIndex = buffer.writerIndex();
+    for (int i = 0; i < size; i++) {
+      byte[] encoded = writingClassDefs.get(i).getEncoded();
+      int bytesLen = encoded.length;
+      buffer.ensure(writerIndex + bytesLen);
+      final byte[] targetArray = buffer.getHeapMemory();
+      System.arraycopy(encoded, 0, targetArray, writerIndex, bytesLen);
+      writerIndex += bytesLen;
     }
-    metaContext.writingClassDefs.clear();
+    buffer.writerIndex(writerIndex);
   }
 
   /**

java/fury-core/src/main/java/org/apache/fury/resolver/MetaContext.java

@@ -19,9 +19,8 @@
 
 package org.apache.fury.resolver;
 
-import java.util.ArrayList;
-import java.util.List;
 import org.apache.fury.collection.IdentityObjectIntMap;
+import org.apache.fury.collection.ObjectArray;
 import org.apache.fury.memory.MemoryBuffer;
 import org.apache.fury.meta.ClassDef;
 
@@ -34,15 +33,15 @@ public class MetaContext {
   public final IdentityObjectIntMap<Class<?>> classMap = new IdentityObjectIntMap<>(8, 0.4f);
 
   /** Class definitions read from peer. */
-  public final List<ClassDef> readClassDefs = new ArrayList<>();
+  public final ObjectArray<ClassDef> readClassDefs = new ObjectArray<>();
 
-  public final List<ClassInfo> readClassInfos = new ArrayList<>();
+  public final ObjectArray<ClassInfo> readClassInfos = new ObjectArray<>();
 
   /**
    * New class definition which needs sending to peer. This will be filled up when there are new
    * class definition need sending, and will be cleared after writing to buffer.
    *
    * @see ClassResolver#writeClassDefs(MemoryBuffer)
    */
-  public final List<ClassDef> writingClassDefs = new ArrayList<>();
+  public final ObjectArray<ClassDef> writingClassDefs = new ObjectArray<>();
 }

java/fury-core/src/main/java/org/apache/fury/resolver/SerializationContext.java

@@ -74,7 +74,7 @@ public void resetWrite() {
     }
     if (scopedMetaShareEnabled) {
       metaContext.classMap.clear();
-      metaContext.writingClassDefs.clear();
+      metaContext.writingClassDefs.size = 0;
     } else {
       metaContext = null;
     }
@@ -85,8 +85,8 @@ public void resetRead() {
       objects.clear();
     }
     if (scopedMetaShareEnabled) {
-      metaContext.readClassInfos.clear();
-      metaContext.readClassDefs.clear();
+      metaContext.readClassInfos.size = 0;
+      metaContext.readClassDefs.size = 0;
     } else {
       metaContext = null;
     }
@@ -98,9 +98,9 @@ public void reset() {
     }
     if (scopedMetaShareEnabled) {
       metaContext.classMap.clear();
-      metaContext.writingClassDefs.clear();
-      metaContext.readClassInfos.clear();
-      metaContext.readClassDefs.clear();
+      metaContext.writingClassDefs.size = 0;
+      metaContext.readClassInfos.size = 0;
+      metaContext.readClassDefs.size = 0;
     } else {
       metaContext = null;
     }

java/fury-core/src/test/java/org/apache/fury/resolver/MetaContextTest.java

@@ -79,7 +79,7 @@ private void checkMetaShared(Fury fury, Object o) {
     Assert.assertEquals(fury.deserialize(bytes1), o);
     fury.getSerializationContext().setMetaContext(new MetaContext());
     Assert.assertEquals(fury.serialize(o), bytes);
-    Assert.assertThrows(NullPointerException.class, () -> fury.serialize(o));
+    Assert.assertThrows(AssertionError.class, () -> fury.serialize(o));
   }
 
   // final InnerPojo will be taken as non-final for writing class def.