import java.io.*;
import java.util.jar.*;
import org.codehaus.plexus.util.*;

JarFile jarFile = new JarFile( new File( basedir, "target/test-1.0.jar" ) );
JarEntry jarEntry = jarFile.getEntry( "META-INF/services/org.apache.maven.Shade" );
String service = IOUtil.toString( jarFile.getInputStream( jarEntry ), "UTF-8" );
jarFile.close();

String[] providers = service.split( "(\r\n)|(\r)|(\n)" );
if ( providers.length != 2 )
{
    throw new IllegalStateException( "Broken provider list: " + service );
}