android - I would like to backport the AndroidKeystore from 4.4, but I receive an "access to class not allowed" -

i propose new security provider

public class backportandroidkeystoreprovider extends provider { private static final long serialversionuid = 1l; public static final string provider_name = "xxxandroidkeystore";  public backportandroidkeystoreprovider() {     super(provider_name, 1.0, "android keystore security provider");      // java.security.keystore     put("keystore." + backportandroidkeystore.name,             backportandroidkeystore.class.getname());      // java.security.keypairgenerator     put("keypairgenerator.rsa",             backportandroidkeypairgenerator.class.getname());    } } 

a keystore provider

class backportandroidkeystore extends java.security.keystorespi {     public static string name = "aa";     @override     public key enginegetkey(string alias, char[] password)         throws nosuchalgorithmexception, unrecoverablekeyexception {     ... } 

and keypair generator.

public class backportandroidkeypairgenerator extends keypairgeneratorspi {   @override   public keypair generatekeypair() {     ... } 

then, register , instantiate key store provider.

security.addprovider(provider); keystore = keystore.getinstance(backportandroidkeystore.name); 

but receive exception

java.lang.illegalaccessexception: access class not allowed 

i can instantiate provider new or newinstance, when it's called in java.security.provider$service.newinstance(provider.java:989) exception throw.

any idea ? can explain why it's not possible ?

thank's