diff --git a/sdk/java/src/main/java/io/juicefs/JuiceFileSystemImpl.java b/sdk/java/src/main/java/io/juicefs/JuiceFileSystemImpl.java
index d66487c66334..4663e4cfbc49 100644
--- a/sdk/java/src/main/java/io/juicefs/JuiceFileSystemImpl.java
+++ b/sdk/java/src/main/java/io/juicefs/JuiceFileSystemImpl.java
@@ -116,7 +116,7 @@ public static interface Libjfs {
 
     int jfs_pread(long pid, int fd, @Out ByteBuffer b, int len, long offset);
 
-    int jfs_write(long pid, int fd, @In byte[] b, int len);
+    int jfs_write(long pid, int fd, @In ByteBuffer b, int len);
 
     int jfs_flush(long pid, int fd);
 
@@ -954,7 +954,7 @@ public void write(byte[] b, int off, int len) throws IOException {
       if (b.length - off < len) {
         throw new IndexOutOfBoundsException();
       }
-      int done = lib.jfs_write(Thread.currentThread().getId(), fd, b, len);
+      int done = lib.jfs_write(Thread.currentThread().getId(), fd, ByteBuffer.wrap(b, off, len), len);
       if (done == EINVAL)
         throw new IOException("stream was closed");
       if (done < 0)
@@ -966,7 +966,7 @@ public void write(byte[] b, int off, int len) throws IOException {
 
     @Override
     public void write(int b) throws IOException {
-      int done = lib.jfs_write(Thread.currentThread().getId(), fd, new byte[]{(byte) b}, 1);
+      int done = lib.jfs_write(Thread.currentThread().getId(), fd, ByteBuffer.wrap(new byte[]{(byte) b}), 1);
       if (done == EINVAL)
         throw new IOException("stream was closed");
       if (done < 0)
@@ -1010,6 +1010,10 @@ public void hsync() throws IOException {
       flush();
       ((FSOutputStream) out).fsync();
     }
+
+    public OutputStream getOutputStream() {
+      return out;
+    }
   }
 
   static class BufferedFSOutputStreamWithStreamCapabilities extends BufferedFSOutputStream
diff --git a/sdk/java/src/test/java/io/juicefs/JuiceFileSystemTest.java b/sdk/java/src/test/java/io/juicefs/JuiceFileSystemTest.java
index 206cccd9839d..45cf28d82947 100644
--- a/sdk/java/src/test/java/io/juicefs/JuiceFileSystemTest.java
+++ b/sdk/java/src/test/java/io/juicefs/JuiceFileSystemTest.java
@@ -29,6 +29,7 @@
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.net.URI;
 import java.nio.ByteBuffer;
 import java.security.PrivilegedExceptionAction;
@@ -134,6 +135,18 @@ public FileSystem run() throws Exception {
     }
   }
 
+  public void testWrite() throws Exception {
+    Path f = new Path("/testWriteFile");
+    FSDataOutputStream fou = fs.create(f);
+    byte[] b = "hello world".getBytes();
+    OutputStream ou = ((JuiceFileSystemImpl.BufferedFSOutputStream)fou.getWrappedStream()).getOutputStream();
+    ou.write(b, 6, 5);
+    ou.close();
+    FSDataInputStream in = fs.open(f);
+    String str = IOUtils.toString(in);
+    assertEquals("world", str);
+  }
+
   public void testReadSkip() throws Exception {
     Path p = new Path("/test_readskip");
     fs.create(p).close();