diff --git a/src/main/c/src/LibUsb.c b/src/main/c/src/LibUsb.c
index 2a76b50..fc762ae 100644
--- a/src/main/c/src/LibUsb.c
+++ b/src/main/c/src/LibUsb.c
@@ -722,44 +722,6 @@ JNIEXPORT void JNICALL METHOD_NAME(LibUsb, freeConfigDescriptor)
     resetConfigDescriptor(env, descriptor);
 }
 
-/**
- * int getDescriptor(DeviceHandle, int, int, ByteBuffer)
- */
-JNIEXPORT jint JNICALL METHOD_NAME(LibUsb, getDescriptor)
-(
-    JNIEnv *env, jclass class, jobject handle, jint type, jint index,
-    jobject data
-)
-{
-    NOT_NULL(env, handle, return 0);
-    NOT_NULL(env, data, return 0);
-    DIRECT_BUFFER(env, data, data_ptr, return 0);
-    libusb_device_handle *dev_handle = unwrapDeviceHandle(env, handle);
-    if (!dev_handle) return 0;
-
-    jlong data_size = (*env)->GetDirectBufferCapacity(env, data);
-    return libusb_get_descriptor(dev_handle, type, index, data_ptr, data_size);
-}
-
-/**
- * int getStringDescriptor(DeviceHandle, int, int, ByteBuffer)
- */
-JNIEXPORT jint JNICALL METHOD_NAME(LibUsb, getStringDescriptor)
-(
-    JNIEnv *env, jclass class, jobject handle, jint index, jint langId,
-    jobject data
-)
-{
-    NOT_NULL(env, handle, return 0);
-    NOT_NULL(env, data, return 0);
-    DIRECT_BUFFER(env, data, data_ptr, return 0);
-    libusb_device_handle *dev_handle = unwrapDeviceHandle(env, handle);
-    if (!dev_handle) return 0;
-
-    jlong data_size = (*env)->GetDirectBufferCapacity(env, data);
-    return libusb_get_string_descriptor(dev_handle, index, langId, data_ptr, data_size);
-}
-
 /**
  * int controlTransfer(DeviceHandle, int, int, int, int, ByteBuffer, int)
  */
diff --git a/src/main/java/de/ailis/usb4java/libusb/LibUsb.java b/src/main/java/de/ailis/usb4java/libusb/LibUsb.java
index bbb439b..afc45cb 100644
--- a/src/main/java/de/ailis/usb4java/libusb/LibUsb.java
+++ b/src/main/java/de/ailis/usb4java/libusb/LibUsb.java
@@ -16,6 +16,8 @@ import java.nio.ByteBuffer;
 import java.nio.IntBuffer;
 import java.nio.LongBuffer;
 
+import de.ailis.usb4java.utils.BufferUtils;
+
 /**
  * Static class providing the constants and functions of libusbx.
  * 
@@ -695,10 +697,8 @@ public final class LibUsb
      * 
      * This function is useful for setting up isochronous transfers, for example
      * you might pass the return value from this function to
-     * libusb_set_iso_packet_lengths() in order to set the length field of every
-     * isochronous packet in a transfer.
-     * 
-     * TODO Link to libusb_set_iso_packet_lengths when implemented
+     * {@link #setIsoPacketLengths(Transfer, int)} in order to set the length
+     * field of every isochronous packet in a transfer.
      * 
      * @param device
      *            A device.
@@ -1288,8 +1288,12 @@ public final class LibUsb
      * @return number of bytes returned in data, or ERROR code on failure
      * 
      */
-    public static native int getDescriptor(final DeviceHandle handle,
-        final int type, final int index, final ByteBuffer data);
+    public static int getDescriptor(final DeviceHandle handle, final int type,
+        final int index, final ByteBuffer data)
+    {
+        return controlTransfer(handle, ENDPOINT_IN, REQUEST_GET_DESCRIPTOR,
+            (type << 8) | index, 0, data, 1000);
+    }
 
     /**
      * Retrieve a descriptor from a device.
@@ -1309,8 +1313,12 @@ public final class LibUsb
      * @return number of bytes returned in data, or LIBUSB_ERROR code on failure
      * @see #getStringDescriptorAscii(DeviceHandle, int, StringBuffer)
      */
-    public static native int getStringDescriptor(final DeviceHandle handle,
-        final int index, final int langId, final ByteBuffer data);
+    public static int getStringDescriptor(final DeviceHandle handle,
+        final int index, final int langId, final ByteBuffer data)
+    {
+        return controlTransfer(handle, ENDPOINT_IN, REQUEST_GET_DESCRIPTOR,
+            (DT_STRING << 8) | index, langId, data, 1000);
+    }
 
     /**
      * Perform a USB control transfer.
@@ -1961,4 +1969,86 @@ public final class LibUsb
      * already complete or cancelled. Another LIBUSB_ERROR code on failure.
      */
     public static native int cancelTransfer(final Transfer transfer);
+
+    public static void fillBulkTransfer(Transfer transfer, DeviceHandle handle,
+        int endpoint, ByteBuffer buffer, TransferCallback callback,
+        Object userData, int timeout)
+    {
+        transfer.setDevHandle(handle);
+        transfer.setEndpoint(endpoint);
+        transfer.setType(TRANSFER_TYPE_BULK);
+        transfer.setTimeout(timeout);
+        transfer.setBuffer(buffer);
+        transfer.setUserData(userData);
+        transfer.setCallback(callback);
+    }
+
+    public static void fillInterruptTransfer(Transfer transfer,
+        DeviceHandle handle, int endpoint, ByteBuffer buffer,
+        TransferCallback callback, Object userData, int timeout)
+    {
+        transfer.setDevHandle(handle);
+        transfer.setEndpoint(endpoint);
+        transfer.setType(TRANSFER_TYPE_INTERRUPT);
+        transfer.setTimeout(timeout);
+        transfer.setBuffer(buffer);
+        transfer.setUserData(userData);
+        transfer.setCallback(callback);
+    }
+
+    public static void fillIsoTransfer(Transfer transfer, DeviceHandle handle,
+        int endpoint, ByteBuffer buffer, int numIsoPackets,
+        TransferCallback callback, Object userData, int timeout)
+    {
+        transfer.setDevHandle(handle);
+        transfer.setEndpoint(endpoint);
+        transfer.setType(TRANSFER_TYPE_ISOCHRONOUS);
+        transfer.setTimeout(timeout);
+        transfer.setBuffer(buffer);
+        transfer.setNumIsoPackets(numIsoPackets);
+        transfer.setUserData(userData);
+        transfer.setCallback(callback);
+    }
+
+    public static void setIsoPacketLengths(Transfer transfer, int length)
+    {
+        for (IsoPacketDescriptor isoDesc: transfer.isoPacketDesc())
+        {
+            isoDesc.setLength(length);
+        }
+    }
+
+    public static ByteBuffer getIsoPacketBuffer(Transfer transfer, int packet)
+    {
+        if (packet >= transfer.numIsoPackets())
+        {
+            return null;
+        }
+
+        IsoPacketDescriptor isoDescriptors[] = transfer.isoPacketDesc();
+        int offset = 0;
+
+        for (int i = 0; i < packet; i++)
+        {
+            offset += isoDescriptors[i].length();
+        }
+
+        return BufferUtils.slice(transfer.buffer(), offset,
+            isoDescriptors[packet].length());
+    }
+
+    public static ByteBuffer getIsoPacketBufferSimple(Transfer transfer,
+        int packet)
+    {
+        if (packet >= transfer.numIsoPackets())
+        {
+            return null;
+        }
+
+        IsoPacketDescriptor isoDescriptors[] = transfer.isoPacketDesc();
+        int offset = isoDescriptors[0].length() * packet;
+
+        return BufferUtils.slice(transfer.buffer(), offset,
+            isoDescriptors[packet].length());
+    }
 }
diff --git a/src/main/java/de/ailis/usb4java/utils/BufferUtils.java b/src/main/java/de/ailis/usb4java/utils/BufferUtils.java
index 4a83b9d..8626598 100644
--- a/src/main/java/de/ailis/usb4java/utils/BufferUtils.java
+++ b/src/main/java/de/ailis/usb4java/utils/BufferUtils.java
@@ -23,4 +23,21 @@ public final class BufferUtils
     {
         return ByteBuffer.allocateDirect(longSize).asLongBuffer();
     }
+
+    public static ByteBuffer slice(final ByteBuffer buffer, final int offset,
+        final int length)
+    {
+        int oldPosition = buffer.position();
+        int oldLimit = buffer.limit();
+
+        buffer.position(offset);
+        buffer.limit(offset + length);
+
+        final ByteBuffer slice = buffer.slice();
+
+        buffer.position(oldPosition);
+        buffer.limit(oldLimit);
+
+        return slice;
+    }
 }