How to fix error of Spongy Castle on Android: could not find class java.awt.datatransfer.DataFlavor

问题

I use lib Spongy Castle for signing and encrypting mail on Android according to this example.

            /* Add BC */
            Security.addProvider(new BouncyCastleProvider());
            /* Open the keystore */
            KeyStore keystore = KeyStore.getInstance("PKCS12", "SC");
            keystore.load(new FileInputStream(pkcs12Keystore),
                    password.toCharArray());
            Certificate[] chain = keystore.getCertificateChain(keyalias);

            /* Get the private key to sign the message with */
            PrivateKey privateKey = (PrivateKey) keystore.getKey(keyalias,
                    password.toCharArray());

            /* Create the SMIMESignedGenerator */
            SMIMECapabilityVector capabilities = new SMIMECapabilityVector();
            capabilities.addCapability(SMIMECapability.dES_EDE3_CBC);
            capabilities.addCapability(SMIMECapability.rC2_CBC, 128);
            capabilities.addCapability(SMIMECapability.dES_CBC);

            ASN1EncodableVector attributes = new ASN1EncodableVector();
            attributes.add(new SMIMEEncryptionKeyPreferenceAttribute(
                    new IssuerAndSerialNumber(new X500Name(
                            ((X509Certificate) chain[0]).getIssuerDN()
                                    .getName()), ((X509Certificate) chain[0])
                            .getSerialNumber())));
            attributes.add(new SMIMECapabilitiesAttribute(capabilities));

            SMIMESignedGenerator signer = new SMIMESignedGenerator();
            signer.addSignerInfoGenerator(new JcaSimpleSignerInfoGeneratorBuilder()
                    .setProvider("SC")
                    .setSignedAttributeGenerator(new AttributeTable(attributes))
                    .build("DSA".equals(privateKey.getAlgorithm()) ? "SHA1withDSA"
                            : "MD5withDSA", privateKey,
                            (X509Certificate) chain[0]));

            /* Add the list of certs to the generator */
            List certList = new ArrayList();
            certList.add(chain[0]);
            Store certs = new JcaCertStore(certList);
            signer.addCertificates(certs);

            /* Sign the message */
            MimeMultipart mm = signer.generate(originalMessage, "SC");
            signedMessage = new MimeMessage(session);

            /* Set all original MIME headers in the signed message */
            Enumeration headers = originalMessage.getAllHeaderLines();
            while (headers.hasMoreElements()) {
                signedMessage.addHeaderLine((String) headers.nextElement());
            }

            /* Set the content of the signed message */
            signedMessage.setContent(mm);
            signedMessage.saveChanges();

            ByteArrayOutputStream out = new ByteArrayOutputStream();
            signedMessage.writeTo(out);

            FileOutputStream f = new FileOutputStream(new File(
                    "/sdcard/MobilePKI/out.txt"));
            f.write(out.toByteArray());
            f.close();

When I run my app, it returns the following error:

11-13 08:54:11.867: E/dalvikvm(13188): Could not find class '[Ljava.awt.datatransfer.DataFlavor;', referenced from method org.spongycastle.mail.smime.handlers.multipart_signed.<clinit>
11-13 08:54:11.890: E/AndroidRuntime(13188): FATAL EXCEPTION: main
11-13 08:54:11.890: E/AndroidRuntime(13188): java.lang.VerifyError: org.spongycastle.mail.smime.handlers.multipart_signed
11-13 08:54:11.890: E/AndroidRuntime(13188):    at java.lang.Class.newInstanceImpl(Native Method)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at java.lang.Class.newInstance(Class.java:1409)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.MailcapCommandMap.getDataContentHandler(MailcapCommandMap.java:609)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.MailcapCommandMap.createDataContentHandler(MailcapCommandMap.java:563)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.DataHandler.getDataContentHandler(DataHandler.java:626)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.activation.DataHandler.writeTo(DataHandler.java:329)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1403)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1745)
11-13 08:54:11.890: E/AndroidRuntime(13188):    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1721)

Source code of Spongy Castle lib seems to need java.awt.datatransfer:

package org.spongycastle.mail.smime.handlers;

import org.spongycastle.mail.smime.SMIMEStreamingProcessor;

import javax.activation.ActivationDataFlavor;
import javax.activation.DataContentHandler;
import javax.activation.DataSource;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.internet.ContentType;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMultipart;

import java.awt.datatransfer.DataFlavor;

import java.io.BufferedInputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Enumeration;

(link: https://github.com/rtyley/spongycastle/blob/spongy-master/scmail-jdk15on/src/main/java/org/spongycastle/mail/smime/handlers/multipart_signed.java)

I think it must import package java.awt and I imported rt.jar (including java.awt.*) into my project but it still has this error.

回答1:

I fixed my error:
+ I download source code of spongycastle lib
+ replace line "import java.awt.datatransfer.DataFlavor;" by "import myjava.awt.datatransfer.DataFlavor;" (package myjava.awt.datatransfer is included in additionnal lib)
+ Rebuild spongycastle lib
+ Using new spongycastle lib

回答2:

I managed to fix this:

0) run become-spongy.sh script(from "spongy-scripts" branch) on the mail package 1) create AndroidManifest.xml in mail/src/main/

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.spongycastle">
</manifest>

2) change mail/build.gradle

apply plugin: 'com.android.library'
dependencies {
    compile 'com.sun.mail:android-mail:1.5.5'
    compile 'com.sun.mail:android:1.5.5'
    compile 'com.madgag.spongycastle:pkix:1.54.0.0'
    compile 'com.madgag.spongycastle:prov:1.54.0.0'
    compile 'com.madgag.spongycastle:core:1.54.0.0'
    testCompile 'junit:junit:4.12'
}

android {
    compileSdkVersion 24
    buildToolsVersion "24.0.0"

    defaultConfig {
        minSdkVersion 15
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

3) In the handler files (spongycastle/mail/src/main/java/org/spongycastle/mail/smime/handlers/): a) remove import java.awt.datatransfer.DataFlavor b) remove replace the java.awt.datatransfer.DataFlavor variables/return types with javax.activation.ActivationDataFlavor

4) In your android project include that folder as module

5) build and have fun ;D

Here you can see what how a working spongycastle mail package looks like:https://github.com/Skywalker-11/spongycastle

Here is an example on how an android app looks like that uses the fixed version to send an encrypted smime message over smtp https://github.com/Skywalker-11/SpongyCastleMailTestApp

来源：https://stackoverflow.com/questions/13357855/how-to-fix-error-of-spongy-castle-on-android-could-not-find-class-java-awt-data

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java

android

bouncycastle

spongycastle