Java 25 Direct Memory Access Benchmark

This diagnostic JMH module compares direct-buffer scalar access paths used to reason about MemoryBuffer on JDK 25:

• MemorySegment.get/set with native-order unaligned layouts.
• MethodHandles.byteBufferViewVarHandle over a direct ByteBuffer.

Each benchmark invocation performs one absolute scalar access at a rolling aligned offset. This is closer to generated serializer calls into MemoryBuffer.writeInt32, _unsafePutInt64, and matching read paths than a bulk array-copy benchmark, while keeping the JDK25 benchmark module free of jdk.unsupported APIs.

Build and run with JDK 25:

cd benchmarks/java25
mvn package
java -jar target/java25-memory-access-benchmarks.jar \
  'org.apache.fory.benchmark.java25.DirectMemoryAccessBenchmark.*' \
  -f 1 -wi 5 -i 5 -t 1 -w 1s -r 1s

Run the direct-to-heap copy benchmark:

java -jar target/java25-memory-access-benchmarks.jar \
  'org.apache.fory.benchmark.java25.DirectToHeapCopyBenchmark.*' \
  -f 1 -wi 5 -i 5 -t 1 -w 1s -r 1s