Editing Comparison of C Sharp and Java (section)

=== Closures ===
A closure is an inline function that captures variables from its lexical scope.

C# supports closures as anonymous methods or [[Anonymous function#C#lambda expressions|lambda expressions]] with full-featured [[Closure (computer science)|closure]] semantics.<ref>{{cite web |url=http://msdn.microsoft.com/en-ca/magazine/cc301810.aspx | work = MSDN Magazine |title=An Introduction to Delegates |date=April 2001 |access-date =23 December 2008 | last = Richter | first = Jeffrey |author-link = Jeffrey Richter}}</ref><ref>{{cite web |url=http://diditwith.net/PermaLink,guid,235646ae-3476-4893-899d-105e4d48c25b.aspx | work = Did it with .NET |title=What's in a Closure? | last = Campbell | first = Dustin |date=9 February 2007 |access-date=23 December 2008 |archive-url=https://web.archive.org/web/20140815085318/http://diditwith.net/PermaLink,guid,235646ae-3476-4893-899d-105e4d48c25b.aspx |archive-date=15 August 2014 |url-status=dead |df=dmy-all}}</ref>

In Java, anonymous inner classes will remain the preferred way to emulate closures until Java 8 has become the new standard. This is a more verbose construction. This approach also has some differences compared to real closures, notably more controlled access to variables from the enclosing scopes: only final members can be referenced. Java 8, however introduces lambdas that fully inherit the current scope and, in fact, do not introduce a new scope.

When a reference to a method can be passed around for later execution, a problem arises about what to do when the method has references to variables/parameters in its lexical scope. C# closures can access any variable/parameter from its lexical scope. In Java's anonymous inner classes, only references to final members of the lexical scope are allowed, thus requiring the developer to mark which variables to make available, and in what state (possibly requiring boxing).