Java to a Google version of the language, and to prevent it being inter-operable with other versions, an idea which was "anathema" to the "write once run anywhere" basis of the language. Because of these differences of view, the negotiations failed to reach a deal and Sun refused Google a license for Java. At this point in time, the OpenJDK implementation offered by Sun was not as mature or complete as the Java Standard Edition. Instead of licensing Java, Google chose to develop a cleanroom version of the Java Standard Edition libraries, developing the libraries from a completely fresh start without any access to Sun's code. This became the engine behind Android's Dalvik virtual machine, a core part of the new system. Part of the virtual machine included 37 API calls and around 11,500 lines of code deemed central to Java, which were taken from Apache Harmony, an open-source cleanroom Java implementation developed by the Apache Software Foundation (ASF). Prior to this, the ASF had tried to obtain necessary licenses from Sun to support the Apache Harmony project as to call it an official Java implementation, but could not, in part due to incompatible licensing with Java's GNU General Public License and ASF's Apache License, nor could it gain access to the Java TCKs to validate the Harmony project against Sun's implementation. Though Google stated they used this code to ensure interoperability with the Java Standard Edition for other programmers, during the second appeal hearing, Google stated that it had used this code for commercial reasons to rapidly complete Android and to avoid the "drudgery" of recreating the code. ASF ceased maintaining the Apache Harmony in 2011, leading Google to take over maintenance of these libraries. Google released a beta of the Android platform on November 5, 2007 then, one week later, the software development kit (SDK) which they noted included some Java technologies. Sun's president Schwartz congratulated Google the same day, saying they had "strapped another set of rockets to the community's momentum and to the vision defining opportunity across our (and other) planets." During the trial, Schwartz said that at that time of Android's release, despite knowing Google may have bypassed their licensing requirements, "We decided to grit our teeth and support it so anyone supporting it would see us as part of the value chain". Oracle announced it would purchase Sun in April 2009 for , and