I guess this because of redundancy, in following code first line already including your jar.

compile fileTree(dir: 'libs', include: ['*.jar']) compile files('libs/NChart3D.jar') 

try to remove compile files('libs/NChart3D.jar'), then clean project and rebuild

I guess this because of redundancy, in following code first line already including your jar.

compile fileTree(dir: 'libs', include: ['*.jar']) compile files('libs/NChart3D.jar') 

try to remove compile files('libs/NChart3D.jar'), then clean project and rebuild

make sure you have following project structure, and note that your jar should go into libs folder and other lib components in jniLibs. This is for android studio 1.0