Bouncer provides automated scanning of Android Market for potentially malicious software without disrupting the user experience. The service performs a set of analyses on new applications, applications already in Android Market, and developer accounts. Once an application is uploaded, the service immediately starts analyzing it for known malware, spyware and trojans. It also looks for behaviors that indicate an application might be misbehaving, and compares it against previously analyzed apps to detect possible red flags. We actually run every application on Google’s cloud infrastructure and simulate how it will run on an Android device to look for hidden, malicious behavior.”]
Source: https://googlemobile.blogspot.com/2012/02/android-and-security.html