Getting NoSuchAlgorithmException when running Secure clients with WSO2 products?

Scenario: 

Secured client   _____\    Secured Proxy  ______\   Unsecured Svc
   (external)                /         (ESB)                    /        (AS)

Apply security policy 5(Sign and Encrypt) on both the client and ESB proxy. 

Problem:

You may encounter the error below. 

org.apache.axis2.AxisFault: Error in encryption

at org.apache.rampart.handler.RampartSender.invoke(RampartSender.java:117)

at org.apache.axis2.engine.Phase.invokeHandler(Phase.java:340)

at org.apache.axis2.engine.Phase.invoke(Phase.java:313)

at org.apache.axis2.engine.AxisEngine.invoke(AxisEngine.java:262)

at org.apache.axis2.engine.AxisEngine.send(AxisEngine.java:427)

at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:406)

at org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:229)

at org.apache.axis2.client.OperationClient.execute(OperationClient.java:165)

at org.apache.axis2.client.ServiceClient.sendReceive(ServiceClient.java:555)

at org.apache.axis2.client.ServiceClient.sendReceive(ServiceClient.java:531)

at SecurityClient.runSecurityClient(SecurityClient.java:103)

at SecurityClient.main(SecurityClient.java:41)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

at java.lang.reflect.Method.invoke(Method.java:597)

at com.intellij.rt.execution.application.AppMain.main(AppMain.java:115)

Caused by: org.apache.rampart.RampartException: Error in encryption

at org.apache.rampart.builder.AsymmetricBindingBuilder.doSignBeforeEncrypt(AsymmetricBindingBuilder.java:568)

at org.apache.rampart.builder.AsymmetricBindingBuilder.build(AsymmetricBindingBuilder.java:90)

at org.apache.rampart.MessageBuilder.build(MessageBuilder.java:147)

at org.apache.rampart.handler.RampartSender.invoke(RampartSender.java:106)

... 16 more

Caused by: org.apache.ws.security.WSSecurityException: An unsupported signature or encryption algorithm was used (unsupported key transport encryption algorithm: No such algorithm: http://www.w3.org/2001/04/xmlenc#rsa-oaep-mgf1p); nested exception is: 

java.security.NoSuchAlgorithmException: Cannot find any provider supporting RSA/ECB/OAEPPadding

at org.apache.ws.security.util.WSSecurityUtil.getCipherInstance(WSSecurityUtil.java:785)

at org.apache.ws.security.message.WSSecEncryptedKey.prepareInternal(WSSecEncryptedKey.java:205)

at org.apache.ws.security.message.WSSecEncrypt.prepare(WSSecEncrypt.java:259)

at org.apache.rampart.builder.AsymmetricBindingBuilder.doSignBeforeEncrypt(AsymmetricBindingBuilder.java:534)

... 19 more

Caused by: java.security.NoSuchAlgorithmException: Cannot find any provider supporting RSA/ECB/OAEPPadding

at javax.crypto.Cipher.getInstance(DashoA13*..)

at org.apache.ws.security.util.WSSecurityUtil.getCipherInstance(WSSecurityUtil.java:777)

... 22 more

Solution:

Import the bcprov-jdk15.jar jar which can be found in wso2esb-4.5.0/repository/axis2/client/lib to the class path of the secured client's project.