WARNING: DSL element ' is obsolete and will be removed at the end of 2018

解决办法,在app的作如下修改：

android {
    ...
dexOptions {
        incremental true //这个去掉
        javaMaxHeapSize "4g"
    }
 ...
 }

javaMaxHeapSize "4g"是指定dex运行时的最大的堆空间。