import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.util.Collections;
import javax.xml.crypto.dsig.CanonicalizationMethod;
import javax.xml.crypto.dsig.DigestMethod;
import javax.xml.crypto.dsig.Reference;
import javax.xml.crypto.dsig.SignatureMethod;
import javax.xml.crypto.dsig.SignedInfo;
import javax.xml.crypto.dsig.XMLSignature;
import javax.xml.crypto.dsig.XMLSignatureFactory;
import javax.xml.crypto.dsig.keyinfo.KeyInfo;
import javax.xml.crypto.dsig.keyinfo.KeyInfoFactory;
import javax.xml.crypto.dsig.keyinfo.KeyValue;
import javax.xml.crypto.dsig.spec.C14NMethodParameterSpec;
public class MainClass {
  public static void main(String[] args) throws Exception {
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("DSA");
    kpg.initialize(1024, new SecureRandom());
    KeyPair dsaKeyPair = kpg.generateKeyPair();
    XMLSignatureFactory sigFactory = XMLSignatureFactory.getInstance();
    Reference ref = sigFactory.newReference("#Body", sigFactory.newDigestMethod(DigestMethod.SHA1, null));
    SignedInfo signedInfo = sigFactory.newSignedInfo(sigFactory.newCanonicalizationMethod(
        CanonicalizationMethod.INCLUSIVE_WITH_COMMENTS, (C14NMethodParameterSpec) null), sigFactory.newSignatureMethod(SignatureMethod.DSA_SHA1, null), Collections.singletonList(ref));
    KeyInfoFactory kif = sigFactory.getKeyInfoFactory();
    KeyValue kv = kif.newKeyValue(dsaKeyPair.getPublic());
    KeyInfo keyInfo = kif.newKeyInfo(Collections.singletonList(kv));
    XMLSignature xmlSig = sigFactory.newXMLSignature(signedInfo, keyInfo);
  }
}