I did solve the problem importing “httpclient-android-4.3.5.jar” (downloaded from here: http://repo1.maven.org/maven2/org/apache/httpcomponents/httpclient-android/4.3.5/) in the project.
But there are still dependencies that cannot be resolved:
import org.apache.commons.lang3.StringUtils;
import lombok.Cleanup;
I solved those importing the following JARs:
http://www.java2s.com/Code/JarDownload/common-lang3/common-lang3.jar.zip
https://projectlombok.org/downloads/lombok.jar