JDK version is 1.8 (is done with the installation of Android Studio to install the JDK)
Public key:

 MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCdHc7rWSuL8JCVRY0PwaeIsHX/gel/hvKA3zi5eH2C2bk9HFGbsNKX2Wg + rbXse0SfLLkF42gzD0ghlc7JeVC8DIJI4ef33UUjfcDyQ1xtsuFZDsIg4hFJPAeuaW0CNM1ydl2c2IzIiNL6AL0q736vkl0rqOS5IKw74/K2uQFcgQIDAQAB 

私钥:

MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBAJ0dzutZK4vwkJVFjQ/Bp4iwdf+B6X+G8oDfOLl4fYLZuT0cUZuw0pfZaD6ttex7RJ8suQXjaDMPSCGVzsl5ULwMgkjh5/fdRSN9wPJDXG2y4VkOwiDiEUk8B65pbQI0zXJ2XZzYjMiI0voAvSrvfq+SXSuo5LkgrDvj8ra5AVyBAgMBAAECgYA1OfXxcQH5pIO2rhs9rUNOYUl4R9CMrXDWC8kxvAn5HD1O4Jsc/Wg6nSJdqYeqF5CFxCbiQcn5EkJDbnbhdkHNCRgbfz/TubcX3KQtax0CRsGwRVj98uQNmoNucVk+J5UPX9LyXXWr+d6WxG2hIFVMg9oo/A/kZe/5v+n6X72tgQJBAO6OdcG5bEpDesUM7Oq+2NzRzkA8dbdkOXbV+811ylFy2IARLdNnaAw3VgjjDQ2DnLAYr/Ows+Y37cKmuuN4R7kCQQComt8l3NQy1S3m2Qh3smOyJ7ipv5U2yHPNZFQekE2IaRKbY3JEWxHDB5rNHY1cJygWMWzanv66I4DL2+dtqw8JAkBoxzefhAK1R5g3zmqM3JBBxQETI7sMdr/qmygC4TaguZGwBlubW/LOUsu+EYPdKK58hgtaPIV3m58ZfMPfPyg5AkBwHUPDTpuADcePGMSLq4Clx8oAfle/bP2sF0nkZPpZed0YnMEv+QrPkC/8suj73UHHuCf1HAKwTcloRZsXjsbZAkEAqPM4NgdRZhUAwRiI1ZBeED4/pIKRQyb3QHPLvuBuvLpxALGVDfxKHHqPz28AAm3+Ska4EERrtIveAq826IdqKA==

Encrypted content:

 MGXvX + LVhDJPhrJXnZai6CDvg8Tgs8eIzFe0i5XKhmu5wcavibVjsYm1 + 3 omoxl3rfs07vq1gm1hqwhtsb9edp4wffrvhdxhcq3tdnocjwf2bycoubiqljx0nysvocprwgsnsvjyknxyhoovrv1wer1v9fmio7u3ju6qo2xv1us=

The right decryption result: what __
Java code: (online copy, and add a constructor)
Because using Java Android. Util. Sdk26 Base64 need, but I want to be compatible to sdk21, so in the Java package the following code into the jar and then direct call...

//
//the Source code recreated the from a. class file by IntelliJ IDEA 
//(powered by Fernflower decompiler) 
//

Package MyBase64; 

Import the Java. Security. KeyFactory; 
Import the Java. Security. PrivateKey; 
Import the Java. Security. PublicKey; 
Import the Java. Security. Signature; 
Import the Java. Security. Spec. PKCS8EncodedKeySpec; 
Import the Java. Security. Spec. X509EncodedKeySpec; 
Import the Java. Util. Base64; 
The import javax.mail. Crypto. Cipher; 

Public class MyBase64 {
Public static final String KEY_ALGORITHM="RSA"; 
Public static final String SIGNATURE_ALGORITHM="MD5withRSA"; 
Private static final ints KEY_SIZE=1024; 
Private static final String PUBLIC_KEY="RSAPublicKey"; 
Private static final String PRIVATE_KEY="RSAPrivateKey"; 
Private static String str_pubK=""; 
Private static String str_priK=""; 

Public MyBase64 (String pubK, String priK) {
Str_priK=priK; 
Str_pubK=pubK; 
} 

Public static PublicKey getPublicKey (String key) throws the Exception {
Byte [] keyBytes=Base64. GetDecoder (). The decode (key); 
X509EncodedKeySpec keySpec=new X509EncodedKeySpec (keyBytes); 
KeyFactory KeyFactory=KeyFactory. GetInstance (" RSA "); 
PublicKey PublicKey=keyFactory. GeneratePublic (keySpec); 
Return publicKey; 
} 

Public PrivateKey getPrivateKey (String key) throws the Exception {
Byte [] keyBytes=Base64. GetDecoder (). The decode (key); 
PKCS8EncodedKeySpec keySpec=new PKCS8EncodedKeySpec (keyBytes); 
KeyFactory KeyFactory=KeyFactory. GetInstance (" RSA "); 
PrivateKey PrivateKey=keyFactory. GeneratePrivate (keySpec); 
Return privateKey; 
} 

Public byte [] sign (byte [] data) throws the Exception {
PrivateKey priK=this. GetPrivateKey (str_priK); 
Signature sig=Signature. GetInstance (" MD5withRSA "); 
Sig. InitSign (priK); 
Sig. Update (data); 
Return sig. Sign (); 
} 

Public Boolean verify (byte [] data, byte [] sign) throws the Exception {
PublicKey pubK=getPublicKey (str_pubK); 
Signature sig=Signature. GetInstance (" MD5withRSA "); 
Sig. InitVerify (pubK); 
Sig. Update (data); 
Return sig. Verify (sign); 
} 

Public byte [] encrypt (byte [] bt_plaintext) throws the Exception {
PublicKey PublicKey=getPublicKey (str_pubK); 
RSA Cipher Cipher=Cipher. GetInstance (" "); 
Cipher. The init (1, publicKey); 
Byte [] bt_encrypted=cipher. DoFinal (bt_plaintext); 
Return bt_encrypted; 
} 

Public byte [] decrypt (String bt_encrypted) throws the Exception {
PrivateKey PrivateKey=this. GetPrivateKey (str_priK); 
RSA Cipher Cipher=Cipher. GetInstance (" "); 
Cipher. The init (2, privateKey); 
Return cipher. DoFinal (Base64. GetDecoder (). The decode (bt_encrypted)); 
} 

Public static void main (String [] args) throws the Exception {
String pub="MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCdHc7rWSuL8JCVRY0PwaeIsHX/gel/hvKA3zi5eH2C2bk9HFGbsNKX2Wg + rbXse0SfLLkF42gzD0ghlc7JeVC8DIJI4ef33UUjfcDyQ1xtsuFZDsIg4hFJPAeuaW0CNM1ydl2c2IzIiNL6AL0q736vkl0rqOS5IKw74/K2uQFcgQIDAQAB"; 
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