error while catkin make in

http://wiki.ros.org/android/Tutorials/kinetic/Installation%20-%20ROS%20Development%20Environment

mkdir -p ~/android_core
wstool init -j4 ~/android_core/src https://raw.github.com/rosjava/rosjava/kinetic/android_core.rosinstall
source /opt/ros/kinetic/setup.bash
# You only need to do the next step if you opted for a source installation of rosjava:
source ~/rosjava/devel/setup.bash
cd ~/android_core
catkin_make

kindly provide me the solution

Base path: /root/android_core
Source space: /root/android_core/src
Build space: /root/android_core/build
Devel space: /root/android_core/devel
Install space: /root/android_core/install
####
#### Running command: "make cmake_check_build_system" in "/root/android_core/build"
####
####
#### Running command: "make -j8 -l8" in "/root/android_core/build"
####

FAILURE: Build failed with an exception.

* What went wrong:
A problem occurred configuring root project 'android_core'.
> Could not resolve all artifacts for configuration ':classpath'.
   > Could not resolve com.android.tools.build:gradle:3.5.2.
     Required by:
         project :
      > Could not resolve com.android.tools.build:gradle:3.5.2.
         > Could not get resource 'https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/3.5.2/gradle-3.5.2.pom'.
            > Could not GET 'https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/3.5.2/gradle-3.5.2.pom'.
               > PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 4s
android_core/CMakeFiles/gradle-android_core.dir/build.make:77: recipe for target 'android_core/CMakeFiles/gradle-android_core' failed
make[2]: *** [android_core/CMakeFiles/gradle-android_core] Error 1
CMakeFiles/Makefile2:428: recipe for target 'android_core/CMakeFiles/gradle-android_core.dir/all' failed
make[1]: *** [android_core/CMakeFiles/gradle-android_core.dir/all] Error 2
Makefile:160: recipe for target 'all' failed
make: *** [all] Error 2
Invoking "make -j8 -l8" failed