CredentialService.java

import org.jboss.logging.Logger;
import org.jboss.msc.service.ServiceContainer;
import org.jboss.msc.service.ServiceController;
import org.jboss.msc.service.ServiceName;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.wildfly.security.credential.PasswordCredential;
import org.wildfly.security.credential.store.CredentialStore;
import org.wildfly.security.credential.store.CredentialStoreException;
import org.wildfly.security.password.Password;
import org.wildfly.security.password.interfaces.ClearPassword;
import javax.annotation.PostConstruct;
import java.util.Arrays;

import org.jboss.as.server.CurrentServiceContainer;

@Service
public class CredentialService {

    private static String passwordSMTP = null;

    private static final ServiceName SERVICE_NAME_CRED_STORE = ServiceName.of("org", "wildfly", "security", "credential-store");

    @PostConstruct
    private void init() throws Exception {
        String credentialStoreName = "STORE_NAME";
        String alias = "SMTP_PASSWORD";
        ServiceContainer registry = CurrentServiceContainer.getServiceContainer();
        ServiceController<?> credStoreService = registry.getService(ServiceName.of(SERVICE_NAME_CRED_STORE, credentialStoreName));
        CredentialStore cs = (CredentialStore) credStoreService.getValue();
        if (cs.exists(alias, PasswordCredential.class)) {
            Password password = cs.retrieve(alias, PasswordCredential.class).getPassword();
            if (password instanceof ClearPassword) {
                passwordSMTP = new String(((ClearPassword) password).getPassword());
            }
        }
    }

    public String getPasswordSMTP() {
        return passwordSMTP;
    }

}

related to medium article https://medium.com/nerd-for-tech/using-jboss-credential-store-in-a-spring-application-4bacfd2d9e96