You can view the uses of some native classes.

j2me_MIDP2_src\src\java\lang\String.java
..............\...\....\....\StringBuffer.java
..............\...\....\util\Calendar.java
..............\...\....\....\Vector.java
..............\...\....\....\Stack.java
..............\...\....\....\Hashtable.java
..............\...\....\....\Enumeration.java
..............\...\....\io\PrintStream.java
..............\...\....\..\OutputStream.java
..............\...\....\..\InputStream.java
..............\...\....\..\DataOutputStream.java
..............\...\....\..\DataInputStream.java
..............\...\....\..\ByteArrayOutputStream.java
..............\...\....\..\ByteArrayInputStream.java
..............\...\....x\microedition\rms\RecordStore.java
..............\...\.....\............\lcdui\game\Sprite.java
..............\...\.....\............\.....\....\TiledLayer.java
..............\...\.....\............\.....\....\Layer.java
..............\...\.....\............\.....\....\LayerManager.java
..............\...\.....\............\.....\Canvas.java
..............\...\.....\............\.....\Alert.java
..............\...\.....\............\.....\ChoiceGroup.java
..............\...\.....\............\.....\CustomItem.java
..............\...\.....\............\.....\Display.java
..............\...\.....\............\.....\Displayable.java
..............\...\.....\............\.....\Form.java
..............\...\.....\............\.....\Gauge.java
..............\...\.....\............\.....\Graphics.java
..............\...\.....\............\.....\ImageItem.java
..............\...\.....\............\.....\Item.java
..............\...\.....\............\.....\Screen.java
..............\...\.....\............\.....\TextField.java
..............\...\.....\............\io\Connector.java
..............\...\.....\............\..\HttpConnection.java
..............\...\.....\............\..\PushRegistry.java

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