Can you example for Cipher getInstance()?

Cipher.getInstance("RSA/ECB/PKCS1Padding") Creates a Cipher object (specifying the algorithm, mode, and padding).

Can JDK 1.4 supports RSA (Assymetric cryptography)algoritm?

RSA. This algorithm is the most popular public key cipher, but it's not supported in JDK 1.4.
You must use a third-party library like BouncyCastle to get this support.