Basic Java Card Applet

Write a Java Card Applet using the Java Card Development Kit 2.2.2 with the following four functions: 1. Write Data, to write an arbitrary buffer to the card with an arbitrary identifier as input parameter. 2. Read Data, to read one of the existing data buffers using one of the identifiers. 3, Verify, to verify a PIN code 4. ChangePin, to change the PIN presenting the current and new value. Each operation must have the corresponding JUnit test.