Issue in mutual certificate authentication

[OR]

So I am trying to implement certificate authentication, here is the code I wrote:

Code:

import java.io.FileInputStream;

import java.io.InputStream;

import java.security.KeyStore;

import com.jayway.restassured.RestAssured;

public class RestAssuredUtil

{

    public static final void setup() throws Exception

    {

        RestAssured.baseURI  = "myRESTAPIURL";

        

        RestAssured.keystore("pathToKeyStoreJKSFile", "Paswd");

        

        String trustStorePath ="pathToTrustStoreJKSFile";

        String trustStorePassword="Paswd";

        KeyStore truststore = KeyStore.getInstance(KeyStore.getDefaultType());

        InputStream truststoreInput = new FileInputStream(trustStorePath);

        

        truststore.load(truststoreInput, trustStorePassword.toCharArray());

        System.out.println("Truststore has " + truststore.size() + " keys");

        

        RestAssured.trustStore(truststore);

        

    }

}

import static com.jayway.restassured.RestAssured.given;

import org.testng.annotations.BeforeTest;

import org.testng.annotations.Test;

public class LanguageWSTest

{

    @BeforeTest

    public void setup() throws Exception

    {

        RestAssuredUtil.setup();

    }

    

    @Test

    public void testRead()

    {

    given()

    .auth().basic("username","password")

        .expect()

              .statusCode(200)

              .log().everything()

        .when()

            .get ("/enpoint");

    }

  }

And I got following error message when I ran it:

Truststore has 3 keys

FAILED: testRead

javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

at sun.security.ssl.Alerts.getSSLException(Unknown Source)

My questions:

1. Is my way to implement it correct? Or do I need it use some other packages/methods?

2. If I am doing it right, what's causing the error? I googled but couldn't find a solution that would fix it.

I'm at my wit's end trying to figure the solution. Kindly help.

Thanks,

OR