An implementation of new API introduced in JDK-Merlin does not work.
Invoking CertPathBuilder.getInstance(String, Provider) causes the following
exception:
java.lang.IllegalArgumentException: argument type mismatch
at java.lang.reflect.Method.invoke(Native Method)
at java.security.cert.CertPathBuilder.getInstance(CertPathBuilder.java:232)

Indeed, in the sources there almost is no difference betweet realization of getInstance(String, String) and getInstance(String, Provider) and in the second
case Security.getImpl(String, String, String) method invoking with wrong parameter.

There is a minimized test :
-------------------------------
import java.security.cert.CertPathParameters;
import java.security.cert.CertPathBuilderResult;
import java.security.cert.CertPathBuilderSpi;
import java.security.Provider;
import java.security.AccessController;
import java.security.cert.CertPathBuilder;
import java.security.NoSuchAlgorithmException;


public class getInstanceTest {

    public static void main(String[] argv) {
        String stubCPB = "StubCPBSpi";
        String stubAlgorithm = "CertPathBuilder.PKIX";
        Provider stubProvider = new StubProvider( stubAlgorithm, stubCPB);
        try {
            CertPathBuilder cpb = CertPathBuilder.getInstance( "PKIX", stubProvider);
            Provider provider = cpb.getProvider();
            if( provider.getName().equals( stubAlgorithm) ) {
                System.out.println(" Algorithm "+stubAlgorithm+" found in the specified provider "+stubProvider);
            } else {
                System.out.println(" Provider name does not match with specified");
                System.out.println(" FAILED ");
            }
        } catch(NoSuchAlgorithmException nsae) {
            System.out.println(" Algorithm "+stubAlgorithm+" has not been found in provider "+stubProvider);
            System.out.println(" FAILED ");
        }
        System.out.println(" OKAY ");
    }
}

class StubProvider extends Provider {
    final String algorithm1;
    final String spiClass1;

    public StubProvider(String algorithm, String spiClass) {
        super( algorithm, 1.1, "No Info");
        this.algorithm1 = algorithm;
        this.spiClass1 = spiClass;
        AccessController.doPrivileged(new java.security.PrivilegedAction() {
            public Object run() {
                put( algorithm1, spiClass1);
                return null;
            } } );

    }
}

class StubCPBSpi extends CertPathBuilderSpi {
    public boolean called;
    public StubCPBSpi() {
        super();
        called = false;
    }
    public CertPathBuilderResult engineBuild(CertPathParameters params) {
        called = true;
        return null;
    }
}

---------------------------- output from the test

:\>java getInstanceTest
Exception in thread "main" java.lang.IllegalArgumentException: argument type mismatch
        at java.lang.reflect.Method.invoke(Native Method)
        at java.security.cert.CertPathBuilder.getInstance(CertPathBuilder.java:232)
        at getInstanceTest.main(getInstanceTest.java:17)