here - Stefan-Marr.de

2. Context and Motivation
2.1. Multi-Language Virtual Machines: Foundation for
Software Ecosystems
High-level language VMs are used as general purpose platforms with large
software ecosystems. The role of high-level language VMs has been shifting
over the past decades. Starting out as interpreted VMs for languages
that offer high productivity, they became VMs that use highly efficient justin-time
compilation technology [Aycock, 2003] and well tuned garbage collectors
[Craig, 2006; Smith and Nair, 2005]. The resulting performance improvements
opened the door for a wide range of application domains. Consequently,
VMs are now the platform for many applications that earlier on
would have been implemented in native languages such as C or C++ and
targeted a particular operating system. With the increased adoption of VMs
came additional support from a wide range of parties. Software and tool vendors,
as well as the various open source communities started to build large
software ecosystems [Gregor, 2009] around VMs. Reasons for this adoption
are availability of libraries, code reuse, portability, and the desire to integrate
different systems on the same platform. Studies such as the one of Ruiz et al.
[2012] show that code reuse in such diverse ecosystems is not merely a theoretical
opportunity, but realized in practice. In addition to code reuse, tooling
is an important motivation. For instance, the availability of IDEs, performance
analysis tools, testing frameworks, and continuous integration techniques are
important factors. Eclipse 1 and Netbeans 2 as IDEs, and tools like VisualVM 3
enable developers to use multiple languages, while relying on the same common
tools.
Language implementers target VMs to provide appropriate abstractions for
specific problem domains. While the adoption of VMs like JVM and CLI
grew over the years, the desire to use different kinds of languages interoperating
with the existing ecosystem, grew as well. Both, JVM and CLI, were
originally tailored towards either one specific language, i. e., Java for the JVM,
or a set of closely related languages, i. e., VB.NET and C# for the CLI. The
resulting VMs were however efficient enough to attract a vast number of lan-
1 http://www.eclipse.org/
2 http://www.netbeans.org/
3 http://visualvm.java.net/
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