@OnClick method from Butterknife crashes app with java.lang.BootstrapMethodError

I was facing the same problem. Butter Knife requires that you enable Java 8 in your builds to function as of version 9.0.0 and newer. This is what worked for me ....

app.gradle

android {
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}

dependencies {
    implementation 'com.jakewharton:butterknife:10.1.0'
    annotationProcessor 'com.jakewharton:butterknife-compiler:10.1.0'
}

apply plugin: 'com.jakewharton.butterknife'

https://developer.android.com/studio/write/java8-support

Sync your gradle file if you are still facing the problem, clean your project and run again.

I solved it by downgrading the library version.

I replaced the following

implementation 'com.jakewharton:butterknife:9.0.0-rc3'
annotationProcessor 'com.jakewharton:butterknife-compiler:9.0.0-rc3'

with

implementation 'com.jakewharton:butterknife:9.0.0-rc1'
annotationProcessor 'com.jakewharton:butterknife-compiler:9.0.0-rc1'