Java Cryptography Extension (JCE) Unlimited Strength

To use AES-256 in Java, you need to install extra policy file. As

If you exported your PKCS#12 file from your browser and used a password that is greater than 7 characters, you may need to download and install the Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files so that Java applications such as the GSI-SSHTerm can read this file. This is a matter of U.S. policy and U.S. export controls (not due to technical reasons).

It seems there are no such restriction in OpenJDK.

http://www.ngs.ac.uk/tools/jcepolicyfiles
http://blogs.adobe.com/ADEP/2011/10/configuring-the-jdk-for-rights-management-encryption-using-aes-256-bit-keys.html