Null pointer exception when calling WSSecEncrypt.prepare()

[Lule Chen]

Hi, dims:

I adopted the code in TestWSSecurityNew15.java that encrypts the soap body, but 
I got the null pointer exception as the following:

Exception in thread "main" java.lang.NullPointerException
        at 
org.apache.ws.security.message.WSSecEncrypt.prepare(WSSecEncrypt.java:197)
        at 
com.nortel.cdma.axis.Client.NEServiceClient.main(NEServiceClient.java:240)

I looked at the line of code in WSSecEncrypt.java, it seems failed at 
 
                this.symmetricKey = keyGen.generateKey();

I suspect that keyGen is null. My code snips are as the following:
 
    static final WSSecurityEngine secEngine = new WSSecurityEngine();
    static final Crypto crypto = 
CryptoFactory.getInstance("cryptoSKI.properties");

...
 
        SOAPEnvelope env = new SOAPEnvelope(new ByteArrayInputStream(byteBuf));
 
        WSSecEncrypt encrypt = new WSSecEncrypt();
        encrypt.setUserInfo("wss4jcert", "security");
        encrypt.setKeyIdentifierType(WSConstants.BST_DIRECT_REFERENCE);
        encrypt.setSymmetricEncAlgorithm("WSConstants.TRIPLE_DES");

        Document doc = env.getAsDocument();
 
        WSSecHeader secHeader = new WSSecHeader();
        secHeader.insertSecurityHeader(doc);
        encrypt.prepare(doc, crypto);
        
...
 
Do you have any idea whats wrong of my code?
 
Thanks,
 
 
Lule