leakcanary-android-no-op - Class,Method not found solution

debug-CustomMultiDexApplication.java

// app/src/debug/java/com/akhil/sampleapp/CustomMultiDexApplication.java
package com.akhil.sampleapp;

import android.support.multidex.MultiDexApplication;

import com.squareup.leakcanary.AndroidExcludedRefs;
import com.squareup.leakcanary.LeakCanary;
import com.squareup.leakcanary.RefWatcher;


public class CustomMultiDexApplication extends MultiDexApplication {
    public RefWatcher refWatcher;

    @Override
    public void onCreate() {
        super.onCreate();
        refWatcher = LeakCanary.install(this, LeakSlackUploadService.class, AndroidExcludedRefs.createAppDefaults().build());
    }
}

release-CustomMultiDexApplication.java

// app/src/release/java/com/akhil/sampleapp/CustomMultiDexApplication.java
package com.akhil.sampleapp;

import android.support.multidex.MultiDexApplication;
import com.squareup.leakcanary.RefWatcher;


public class CustomMultiDexApplication extends MultiDexApplication {
    public RefWatcher refWatcher;

}