Multiple dex files define Landroid/support/annotat

Make sure every module use the same version of support libraries! for example:
compile 'com.android.support:support-v4:23.2.0'
compile 'com.android.support:appcompat-v7:23.2.0'

exclude confict in main module:
compile(project(':your_lib_module')) {
exclude group: 'com.android.support', module: 'appcompat-v7'
exclude group: 'com.android.support', module: 'support-v4'
exclude group: 'com.android.support', module: 'support-annotations'
}

In all modules which use support libraries, execute: ant clean, gradle clean;

try to build again.