Android- Error:Execution failed for task ':app:transformClassesWithDexForRelease'

i fixed it just this code.

local.properties

org.gradle.jvmargs=-XX\:MaxHeapSize\=512m -Xmx512m

and you should do this changing on gradle

defaultConfig {
    applicationId "yourProjectPackage"
    minSdkVersion 15
    versionCode 1
    versionName "1.0"
    targetSdkVersion 23

    multiDexEnabled true //important
}