D8: Cannot fit requested classes in a single dex file (# methods: 91917 > 65536) com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives: code example

Example 1: D8: Cannot fit requested classes in a single dex file (# methods: 85258 > 65536)

defaultConfig {
    ...

    multiDexEnabled true
}

Example 2: Cannot fit requested classes in a single dex file (# methods: 65710 > 65536)

android {
    defaultConfig {
        ...
        minSdkVersion 21 <----- *here
        targetSdkVersion 26
        multiDexEnabled true <------ *here
    }
    ...
}