Using the LeakCanary that is a memory leak detection library for Android and Java.

AndroidManifest.xml

<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="xxx">

    <application
        android:name=".MyApplication"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme">
      
      ...
      
    </application>
</manifest>

build.gradle

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    compile "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
    debugCompile 'com.squareup.leakcanary:leakcanary-android:1.4-beta2'
    releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.4-beta2'
    testCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.4-beta2'
}

MyApplication.kt

package xxx

import android.app.Application
import com.squareup.leakcanary.LeakCanary

class MyApplication : Application() {

    override fun onCreate() {
        super.onCreate()
        LeakCanary.install(this)
    }
}