This is a comparison of the C# programming language with the Java programming language. As two modern garbage-collected runtime-compiled languages derived from C and C++, there are many similarities between Java and C#. However, there are many differences also, with C# being described as a hybrid of C++ and Java^[1], with additional new features and changes. This page documents the strong general similarities of the languages and then points out those instances where the languages differ. Both languages were designed carefully, and if one language has a feature another lacks, it may be the result of a conscious design decision. Thus, the reader is advised to avoid the temptation to 'keep score,' and instead think about why the designers made each decision. Programming languages are used for controlling the behavior of a machine (often a computer). ... Programming languages are used for controlling the behavior of a machine (often a computer). ... // Programming language statements typically have conventions for: statement separators; statement terminators; and line continuation A statement separator is used to demarcate boundaries between two separate statements. ... // Different languages use different symbols for the concatenation operator. ... This article presents string functions given in computer programming. ... In computer science, an evaluation strategy is a set of (usually deterministic) rules for determining the evaluation of expressions in a programming language. ... The nearest living sibling to ALGOL 68 may be C++, making this a good comparison candidate: C++ doesnt have: PROC - nested functions, OP and PRIO - definable operator symbols and priorities, garbage collection, use before define, formatted transput using complex formatting declarations, := - assignment operation symbol (to avoid confusion with equal... The C and C++ programming languages are closely related, as C++ grew out of C and is many ways a superset of the latter. ... This article or section is in need of attention from an expert on the subject. ... This is a comparison of the Java programming language with the C++ programming language. ... The original . ... This is a comparison of the ABAP with the Java programming language. ... C# (pronounced see-sharp) is an object-oriented programming language developed by Microsoft as part of their . ... “Java language” redirects here. ... In computer science, garbage collection (GC) is a form of automatic memory management. ... C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... C++ (pronounced see plus plus, IPA: ) is a general-purpose programming language with high-level and low-level capabilities. ...

Language

Object handling

Both languages are object oriented from the ground up, with a syntax similar to C++. (C++ in turn is derived from C.) Neither language is a superset of C or C++, however. Both use garbage collection as a means of reclaiming memory resources, rather than explicit deallocation of memory. And both include thread synchronization mechanisms as part of their language syntax. Object-oriented programming (OOP) is a computer programming paradigm in which a software system is modeled as a set of objects that interact with each other. ... C++ (pronounced see plus plus, IPA: ) is a general-purpose programming language with high-level and low-level capabilities. ... C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... In computer science, garbage collection (GC) is a form of automatic memory management. ... Synchronization (or Sync) is a problem in timekeeping which requires the coordination of events to operate a system in unison. ...

Both Java and C# have strong and weak object references. Java allows registering a listener that will be notified when a reference is garbage collected, which allows for the good performance of the WeakHashMap that C# lacks. C# only supports this by using a finalizer (which is also available in Java). C# on the other hand allows the programmer to suppress the finalizer of a specific object (e.g., an SQL connection or a file stream that always needs to be properly closed). This can be very useful since finalizers are expensive in generational garbage collection (applied by both Java and .NET), and are often used only as a fail-safe for when the programmer does not close the object. An object with a finalizer will normally be promoted to an extra generation and kept alive longer before it is collected. In object-oriented programming languages that use automatic garbage collection, a finalizer is a special method that is executed when an object is garbage collected. ... Garbage collection can refer to two different things: Garbage collection (computer science): an automatic way of reclaiming unused storage; Civic garbage collection: waste management. ...

C# allows restricted use of pointers, which are considered unsafe by some language designers. C# addresses that concern by requiring that code blocks or methods that use the feature be marked with the unsafe keyword, so that all clients of such code can be aware that the code may be less secure than otherwise. The compiler requires the /unsafe switch to allow compilation of a program that uses such code. Generally, unsafe code is either used to allow better interoperability with unmanaged APIs or system calls (which are inherently "unsafe"), or for performance reasons. It has been suggested that Software pointer be merged into this article or section. ... Interoperability is connecting people, data and diverse systems. ...

Data types

Both languages support the idea of primitive types (known as value types in C#). C# has more primitive types than Java, with unsigned as well as signed integer types being supported, and a special decimal type for decimal floating-point calculations. Java lacks unsigned types. In particular, Java lacks a primitive type for an unsigned byte. Strings are treated as (immutable) objects in both languages, but support for string literals provides a specialized means of constructing them. C# also allows verbatim strings for quotation without escape sequences, which also allow newlines. In computer science, primitive types — as distinct from composite types — are data types provided by a programming language as basic building blocks. ... In computer science, primitive types — as distinct from composite types — are data types provided by a programming language as basic building blocks. ... Signedness is a property of an integer number used by a compiler to indicate if variables of a numeric type are capable of storing both positive and negative numbers, or just positive. ... Signedness is a property of an integer number used by a compiler to indicate if variables of a numeric type are capable of storing both positive and negative numbers, or just positive. ... In computer science a byte (pronounced bite) is a unit of measurement of information storage, most often consisting of eight bits. ... In computer programming and formal language theory, (and other branches of mathematics), a string is an ordered sequence of symbols. ... In computing, immutable refers to: the immutable design pattern in programming an immutable object in object-oriented programming This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... As a linguistic term, verbatim means an exact reproduction of a sentence, phrase, quote or other sequence of text from one source into another. ...

Both allow automatic boxing and unboxing to translate primitive data to and from their object form. Effectively, this makes the primitive types a subtype of the Object type. In C# this also means that primitive types can define methods, such as an override of Object's ToString() method. In Java, separate primitive wrapper classes provide such functionality, which means it requires a static call Integer.toString(42) instead of an instance call 42.ToString(). Another difference is that Java makes heavy use of boxed types in generics (see below), and as such allows an implicit unboxing conversion (in C# this requires a cast). This conversion can potentially throw a null pointer exception, which may not be obvious by code review in Java. In computer science, an object type (a. ... In computer science, an object type (a. ... A primitive wrapper class in the Java programming language is one of eight classes provided in the java. ... Generic programming is a style of computer programming where algorithms are written in an extended grammar and are made adaptable by specifying variable parts that are then somehow instantiated later by the compiler with respect to the base grammar. ... In computer science, type conversion or typecasting refers to changing an entity of one data type into another. ... Code review is peer review of computer source code intended to find and fix mistakes overlooked in the initial development phase, improving overall code quality. ...

C# allows the programmer to create user-defined value types, using the struct keyword. From the programmer's perspective, they can be seen as lightweight classes. Unlike regular classes, and like the standard primitives, such value types are allocated on the stack rather than on the heap. They can also be part of an object (either as a field or boxed), or stored in an array, without the memory indirection that normally exists for class types. Structs also come with a number of limitations. Because structs have no notion of a null value and can be used in arrays without initialization, they always come with an implicit default constructor that essentially fills the struct memory space with zeroes. The programmer can only define additional constructors with one or more arguments. This also means that structs lack a virtual method table, and because of that (and the fixed memory footprint), they cannot allow inheritance (but can implement interfaces). In computer science, primitive types — as distinct from composite types — are data types provided by a programming language as basic building blocks. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... This article or section should be merged with Dynamic memory allocation In Heap Based Memory Allocation, the memory is allocated from a large pool of unused memory area called the heap dynamically. ... A virtual method table, virtual function table, dispatch table, or vtable, is a mechanism used in programming language implementations in order to support dynamic polymorphism, i. ...

Enumerations in C# are derived from a primitive integer type. Any value of the underlying primitive type is a valid value of the enumeration type, though an explicit cast may be needed to assign it. This allows one to combine enumeration values together using the bitwise OR operator if they are bit flags. Enumeration values in Java, on the other hand, are objects. The only valid values in a Java enumeration are the ones listed in the enumeration. A special enumeration set object is needed to combine enumeration values together. Java enumerations allow differing method implementations for each value in the enumeration. Both C# and Java enumerations can be converted to strings. In computer programming, a bitwise operation operates on one or two bit patterns or binary numerals at the level of their individual bits. ...

Arrays

Array and collection types are also given significance in the syntax of both languages, thanks to an iterator-based foreach statement loop. In both languages an array corresponds to an object of the Array class, although in Java this class does not implement any of the collection interfaces. C# has true multi-dimensional arrays, as well as the arrays-of-arrays that are available in Java (and which in C# are commonly called jagged arrays). Multi-dimensional arrays can in some cases increase performance because of increased locality (as there is a single pointer dereference, instead of one for every dimension of the array as is the case for jagged arrays). Another advantage is that the entire multi-dimensional array can be allocated with a single application of operator new, while jagged arrays require explicit loops and allocations for every dimension. In computer science, an iterator is an object which allows a programmer to traverse through all the elements of a collection, regardless of its specific implementation. ... For each (or foreach) is a computer language idiom for traversing items in a collection. ... This article does not cite any references or sources. ... In computer programming, a group of homogeneous elements of a specific data type is known as an array, one of the simplest data structures. ... Memory Locality is a term in computer science used to denote the temporal or spatial proximity of memory access. ...

Inner classes

Both languages allow inner classes, where a class is defined entirely within another class. In Java, these classes have access to both the static and non-static members of the outer class (unless the inner class is declared static, then it only has access to the static members). Local classes can be defined within a method and have access to the method's local variables declared final, and anonymous local classes allow the creation of class instances that override some of their class methods.

C# only provides static inner classes, and requires an explicit reference to the outer class to its non-static members; no local inner classes are supported. Instead, C# provides anonymous delegates as a construct that can provide access to local variables and members (see Event handling). A delegate is a form of type-safe function pointer used in the . ...

Generics

Further information: Generic programming

Both languages now support generics programming, but they have taken different paths to its implementation. Generic programming is a style of computer programming where algorithms are written in an extended grammar and are made adaptable by specifying variable parts that are then somehow instantiated later by the compiler with respect to the base grammar. ...

Generics in Java are a language-only construction; they are implemented only in the compiler. The generated classfiles include generic signatures only in the form of metadata (allowing the compiler to compile new classes against them). The runtime has no knowledge of the generic type system, which meant that JVM implementations only needed minimal updates to handle the new class format. Generics were added to the Java programming language in 2004 as part of J2SE 5. ...

To achieve this goal the compiler replaces all generic types by their upper bounds and inserts casts appropriately in the various places where the type is used. The resulting byte code will contain no references to any generic types or parameters. This technique of implementing generics is known as type erasure. This means that runtime information about the actual types is not available at runtime, and imposes some restrictions such as the inability to create new instances or arrays of generic type arguments. (See also Generics in Java.) The term Generic programming first appeared in object oriented languages with the appearance of generic types. ... Generics were added to the Java programming language in 2004 as part of J2SE 5. ...

C# took a different route. Support for genericity was integrated into the virtual execution system itself and first appeared in .NET 2.0. The language then becomes merely a front-end for the underlying generics support in the execution system. As in Java, the compiler provides static type safety checking, but additionally the JIT performs load time verification of the correctness. Information on generic types is fully preserved at runtime, and allows complete reflection support as well as instantiantion of generic types. In computing, a loader is a program that performs the functions of a linker program and then immediately schedules the resulting executable program for action (in the form of a memory image), without necessarily saving the program as an executable file. ...

Java's approach requires additional run time type checks, it does not guarantee that generic contract will be followed, and lacks reflection on the generic types. Java does not allow to specialize generic classes with primitive types, while C# allows generics for both reference types and value types, including primitive types. Java instead allows the use of boxed types as type parameters (e.g., List<Integer> instead of List<int>), but this comes at a cost since all such values need to be heap-allocated. In both Java and C#, generic specializations that use different reference types share equivalent underlying code,^[2] but for C# the Common Language Runtime (CLR) dynamically generates optimized code for specializations on value types. In computer science, runtime describes the operation of a computer program, the duration of its execution, from beginning to termination (compare compile time). ... The Common Language Runtime (CLR) is the virtual machine component of Microsofts . ...

Notation and special features

Special feature keywords

 // Create a small file "test.txt", write a string, and close it (even if an exception occurs) using (StreamWriter file = new StreamWriter("test.txt")) { file.Write("test"); } 

 switch(color) { case Color.Blue: Console.WriteLine("Color is blue"); break; case Color.DarkBlue: Console.WriteLine("Color is dark"); goto case Color.Blue; // ... } 

 public static IEnumerable<int> GetEven(IEnumerable<int> numbers) { foreach (int i in numbers) { if (i % 2 == 0) yield return i; } } 

In information processing, properties are transmitted by objects and received by observers. ... Used mainly in object-oriented programming, the term method refers to a piece of code that is exclusively associated either with a class (called class methods or static methods) or with an object (called instance methods). ... A parameter is a variable which can be accepted by a subroutine. ... In computer programming, a switch statement is a type of control statement that exists in most modern imperative programming languages (e. ... Strictfp is a Java keyword used to restrict floating point calculations to ensure portability. ... The term arithmetic overflow or simply overflow has the following meanings. ... GOTO is a command found in many programming languages which instructs the computer to jump to another point in the computer program, specified by a label or line number. ... Fig. ... This article or section does not adequately cite its references or sources. ... In computer science control flow (or alternatively, flow of control) refers to the order in which the individual statements, instructions or function calls of an imperative or functional program are executed or evaluated. ... In computer science, an iterator is an object which allows a programmer to traverse through all the elements of a collection, regardless of its specific implementation. ... In computer science, a generator is a special routine that can be used to control the iteration behaviour of a loop. ... Boilerplate refers to any text that is or can be reused in new contexts or applications without being changed much from the original. ...

Event handling

Java requires the programmer to implement the observer pattern manually, though it provides some syntactic sugar in form of anonymous inner classes, which allow one to define the body of the class and create an instance of it in a single point in the code. This is typically used to create observers. The observer pattern (sometimes known as publish/subscribe) is a design pattern used in computer programming to observe the state of an object in a program. ... Syntactic sugar is a term coined by Peter J. Landin for additions to the syntax of a computer language that do not affect its functionality but make it sweeter for humans to use. ... In object-oriented programming, an inner class is a class defined entirely within another class. ...

C# provides extensive support for event-driven programming at language level, including delegate types. These are type-safe references to methods and can be combined to allow multicasting. To support them there is a special syntax to define events in classes and operators to register, unregister or combine event handlers. Delegates support covariance and contravariance, and can be created as anonymous methods with full-featured closure semantics. Event-driven programming is a computer programming paradigm. ... A delegate is a form of type-safe function pointer used in the . ... Multicast is the delivery of information to multiple destinations simultaneously using the most efficient strategy to deliver the messages over each link of the network only once and only create copies when the links to the destinations split. ... A covariant type operator in a type system preserves the ordering of types. ... In computer science, a closure is a function that is evaluated in an environment containing one or more bound variables. ...

Closures have also been proposed as a new feature for Java SE 7. ^[3] Like delegates in C#, such closures would have full access to all local variables in scope, not just read-only access to those marked final (as with anonymous inner classes).

Numeric applications

To adequately support applications in the field of mathematic and financial computation, several language features exist.^[4] In this category, Java provides the strictfp keyword, that enables strict floating-point calculations for a region of code. This will ensure that calculations return the exact same result on all platforms. C# provides no equivalent, but does provide the built-in decimal type, for accurate decimal floating-point calculations. This forgoes the problems that exist with binary floating-point representations (float, double). Such binary representations are not suited to accurately represent decimal numbers and hence introduce rounding errors. For financial applications, an accurate decimal type is essential. Since Java 5.0, the BigDecimal class also provides such characteristics for Java.^[5] BigDecimal and BigInteger are types provided with Java that allow arbitrary-precision representation of numbers. The current release of the .NET framework (3.0) does not currently include such classes, although third party implementations exist as well as an implementation in the upcoming CLR version 3.5.^[6] Strictfp is a Java keyword used to restrict floating point calculations to ensure portability. ...

In Java there is no way to provide the same level of integration for library-defined types such as BigDecimal or complex numbers as there is for the primitive types. For this purpose, C# provides the following: In mathematics, a complex number is a number of the form where a and b are real numbers, and i is the imaginary unit, with the property i 2 = −1. ...

• Operator overloading and indexers providing convenient syntax (see below).
• Implicit and explicit conversions; allow conversions such as exist for the built-in int type that can implicitly convert to long.
• Valuetypes and generics based on valuetypes; in Java every custom type must be allocated on the heap, which is detrimental for performance of both custom types and collections.

In addition to this, C# can help mathematic applications with the checked and unchecked operators that allow to enable or disable run-time checking for arithmetic overflow for a region of code. It also offers rectangular arrays, that have advantages over regular nested arrays for certain applications.^[4] In computer programming, operator overloading (less commonly known as operator ad-hoc polymorphism) is a specific case of polymorphism in which some or all of operators like +, = or == have different implementations depending on the types of their arguments. ... The term arithmetic overflow or simply overflow has the following meanings. ...

Operator overloading

C# includes a large number of notational conveniences over Java, many of which, such as operator overloading and user-defined casts, are already familiar to the large community of C++ programmers. It also has "Explicit Member Implementation" which allows a class to specifically implement methods of an interface, separate to its own class methods, or to provide different implementations for two methods with the same name and signature inherited from two base interfaces. In computer programming, operator overloading (less commonly known as operator ad-hoc polymorphism) is a specific case of polymorphism in which some or all of operators like +, = or == have different implementations depending on the types of their arguments. ... In computer science, type conversion or typecasting refers to changing an entity of one data type into another. ... An interface defines the communication boundary between two entities, such as a piece of software, a hardware device, or a user. ...

C# includes indexers which can be considered a special case of operator overloading (like C++ operator[]), or parametrized get/set properties. An indexer is a property named this[] which uses one or more parameters (indexes); the indexes can be objects of any type:

 myList[4] = 5; string name = xmlNode.Attributes["name"]; orders = customerMap[theCustomer]; 

Java does not include operator overloading in order to prevent abuse of the feature, and to keep the language simpler.^[7] C# allows operator overloading (subject to certain restrictions to ensure logical coherence), which, when used carefully, can make code succinct and more readable.

Methods

Methods in C# are non-virtual by default, and have to be declared virtual explicitly if desired. In Java, all non-static non-private methods are virtual. Virtualness guarantees that the most recent override for the method will always be called, but incurs a certain runtime cost on invocation as these invocations cannot be normally inlined, and require an indirect call via the virtual method table. Some JVM implementations, including the Sun reference implementation, implement inlining of the most commonly called virtual methods to reduce the runtime overhead from virtual method calls. In object-oriented programming (OOP), a virtual function or virtual method is a function whose behavior, by virtue of being declared virtual, is determined by the definition of a function with the same signature furthest in the inheritance lineage of the instantiated object on which it is called. ... Method overriding, in object oriented programming, is a language feature that allows a subclass to provide a specific implementation of a method that is already provided by one of its superclasses. ... In-line expansion or inlining for short is a compiler optimization which expands a function call site into the actual implementation of the function which is called, rather than each call transferring control to a common piece of code. ... A virtual method table, virtual function table, dispatch table, or vtable, is a mechanism used in programming language implementations in order to support dynamic polymorphism, i. ...

In Java there is no way to make methods non-virtual (although they can be "sealed" by using the final modifier to disallow overriding). This means that there is no way to let derived classes define a new, unrelated method with the same name. This can be a problem when a base class is designed by a different person, and a new version introduces a method with the same name and signature as some method already present in the derived class. In Java, this will mean that the method in the derived class will implicitly override the method in the base class, even though that was not the intent of the designers of either class. To prevent this versioning problem, C# requires explicit declaration of intent when overriding virtual methods in a derived class. If a method should be overridden, the override modifier must be specified. If overriding is not desired, and the class designer merely wishes to introduce a new method shadowing the old one, the new keyword must be specified. The new and override keywords also avoid the problem which can arise from a base class being extended with a protected/public method whose signature is already in use by a derived class. In Java a recompilation will lead the compiler to regard the method of the derived class as an override of the method of the base class, which was probably not the intent of the base class developer. The C# compiler will regard the method as if new had been specified, but will issue a warning to that effect. In object-oriented programming, a subclass is a class that inherits some properties from its superclass. ... In biology, a superclass is a taxonomic grade intermediate between subphylum and class. ...

To partially accommodate for these versioning problems, Java 5.0 introduced the @Override annotation, but to preserve backwards compatibility it could not be made compulsory, so it cannot prevent the above accidental overriding situation. Like the override keyword in C#, it can however help ensure that a method in the base class with the same signature exists and is correctly overridden. Annotation is extra information associated with a particular point in a document or other piece of information. ...

Conditional compilation

Unlike Java, C# implements conditional compilation using preprocessor directives. It also provides a Conditional attribute to define methods that are only called when a given compilation constant is defined. This way, assertions can be provided as a framework feature with the method Debug.Assert(), which is only evaluated when the DEBUG constant is defined. Since version 1.4, Java provides a language feature for assertions that can be enabled and disabled at runtime. A directive is an instruction to a programming language compiler about how to compile a program. ... Annotation is extra information associated with a particular point in a document or other piece of information. ... The braces are included in the comment in order to help distinguish this use of a comment from other uses. ...

Namespaces and source files

C#'s namespaces are similar to those in C++. Unlike package names in Java, a namespace is not in any way tied to location of the source file. While it's not strictly necessary for a Java source file location to mirror its package directory structure, it is the conventional organisation. C++ (pronounced see plus plus, IPA: ) is a general-purpose programming language with high-level and low-level capabilities. ... A Java package is a Java programming language mechanism for organizing classes into namespaces. ...

Both languages allow importing of classes (e.g., import java.util.* in Java), allowing a class to be referenced using only its name. Sometimes classes with the same name exist in multiple namespaces or packages. Such classes can be referenced by using fully qualified names, or by importing only selected classes with different names. To do this, Java allows importing a single class (e.g., import java.util.List). C# allows importing classes under a new local name using the following syntax: using Console = System.Console. It also allows importing specializations of classes in the form of using IntList = System.Collections.Generic.List<int>.

Java has a static import syntax that allows using the short name of some or all of the static methods/fields in a class (e.g., allowing foo(bar) where foo() can be statically imported from another class). C# has a static class syntax (not to be confused with static inner classes in Java), which restricts a class to only contain static methods. C# 3.5 will introduce extension methods to allow users to statically add a method to a type (e.g., allowing foo.bar() where bar() can be an imported extension method working on the type of foo). // One of the features of C# 3. ...

The Sun Microsystems Java compiler requires that a source file name must match the only public class inside it, while C# allows multiple public classes in the same file, and puts no restrictions on the file name. As of Version 2, C# allows a class definition to be split into several files, by using the partial keyword in the source code. Sun Microsystems, Inc. ...

Exception handling

Java supports checked exceptions (in addition to unchecked exceptions). C# only supports unchecked exceptions. Checked exceptions enforce the programmer to declare all exceptions thrown in a method, and to catch all exceptions thrown by a method invocation. Exception handling is a programming language construct or computer hardware mechanism designed to handle runtime errors or other problems (exceptions) which occur during the execution of a computer program. ... Exception handling is a programming language construct or computer hardware mechanism designed to handle runtime errors or other problems (exceptions) which occur during the execution of a computer program. ...

Some would argue^{[attribution needed]} that checked exceptions are very helpful for good programming practice, ensuring that all errors are dealt with. Others, including Anders Hejlsberg, chief C# language architect, argue that they were to some extent an experiment in Java and that they haven't been shown to be worthwhile except for in small example programs.^[8][9] One criticism is that checked exceptions encourage programmers to use an empty catch block, resulting only in code bloat: catch (Exception e) {}. Another criticism of checked exceptions is that a new implementation of a method may cause unanticipated checked exceptions to be thrown, which is a contract-breaking change. This can happen in methods implementing an interface that only declares limited exceptions, or when the underlying implementation of a method changes. To allow for such unanticipated exceptions to be thrown, some programmers simply declare the method can throw any type of exception ("throws Exception"), which defeats the purpose of checked exceptions. In some cases however, exception chaining can be applied instead; re-throwing the exception in a wrapper exception. For example, if an object is changed to access a database instead of a file, an SQLException could be caught and re-thrown as an IOException, since the caller may not need to know the inner workings of the object. Anders Hejlsberg (born December 1960[1]) is a prominent Danish software engineer who co-designed several popular and commercially successful programming languages and development tools. ... It has been suggested that this article or section be merged into Software bloat. ... Exception chaining AKA exception wrapping is an object-oriented programming technique of wrapping exceptions into exceptions by saving original exception, i. ...

There are also differences between the two languages in treating the try-finally statement. The finally is always executed, even if the try block contains control-passing statements like throw or return. In Java, this may result in unexpected behavior if the try block is left by a return statement with some value, and then the finally block that is executed afterwards is also left by a return statement with a different value. C# resolves this problem by prohibiting any control-passing statements like return or break in the finally block.

A common reason for using try-finally blocks is to guard resource managing code, so that precious resources are guaranteed to be released in the finally block. C# features the using statement as a syntactic shorthand for this common scenario, in which the Dispose() method of the object of the using is always called.

Lower level code

The Java Native Interface (JNI) feature allows Java programs to call non-Java code. However, JNI does require the code to be called to follow several conventions and impose restrictions on types and names used. This means that an extra adaption layer between legacy code and Java is often needed. This adaption code must be coded in a non-Java language, often C or C++. The Java Native Interface (JNI) is a programming framework that allows Java code running in the Java virtual machine (VM) to call and be called by native applications (programs specific to a hardware and operating system platform) and libraries written in other languages, such as C, C++ and assembly. ...

In addition, third party libraries provide for Java-COM bridging, e.g. JACOB (free), and J-Integra for COM (proprietary). Illustration of an application which may use libvorbisfile. ... Component Object Model (COM) is a platform for software componentry introduced by Microsoft in 1993. ... This article is about free software as used in the sociopolitical free software movement; for non-free software distributed without charge, see freeware. ... It has been suggested that closed source be merged into this article or section. ...

.NET Platform Invoke (P/Invoke) offers the same capability by allowing calls from C# to what Microsoft refers to as unmanaged code. Through metadata attributes the programmer can control exactly how the parameters and results are marshalled, thus avoiding the need for extra adaption code. P/Invoke allows almost complete access to procedural APIs (such as Win32 or POSIX), but no direct access to C++ class libraries. Platform Invocation Services, commonly referred to as just P/Invoke, is a feature of Common Language Infrastructure implementations, like Microsofts Common Language Runtime, that enables managed code to call native code in dynamic-linked libraries (DLLs). ... It has been suggested that this article or section be merged with Byte-code. ...

In addition, .NET Framework also provides a .NET-COM bridge, allowing access to COM components as if they were native .NET objects.

C# also allows the programmer to disable the normal type-checking and other safety features of the CLR, which then enables the use of pointer variables. When this feature is used, the programmer must mark the code using the unsafe keyword. JNI, P/Invoke, and "unsafe" code are equally risky features, exposing possible security holes and application instability. An advantage of unsafe, managed code over P/Invoke or JNI is that it allows the programmer to continue to work in the familiar C# environment to accomplish some tasks that otherwise would require calling out to unmanaged code. A program or assembly using unsafe code must be compiled with a special switch and will be marked as such. This enables runtime environments to take special precautions before executing potentially harmful code. The Common Language Runtime (CLR) is the virtual machine component of Microsofts . ... It has been suggested that this article or section be merged into Pointer. ...

Language history and evolution

Java

Java is older than C# and has built up a large and highly active user base, becoming the lingua franca in many modern branches of computer science, particularly areas which involve networking.^{[citation needed]} Java dominates programming courses at high school and college level in the United States, and there are currently more Java than C# books.^[10] Java's maturity and popularity have ensured more third party Java API and libraries (many of them open source) than C#. In November 2005^[11], there were more Java projects on Sourceforge than for any other language, including C and C++ (more than 16000 projects by end 2005, almost 24000 by end 2006). By contrast, there were less than 3000 C# projects by the end of 2005, and less than 6000 by the end of 2006^[12] (see also ^[13] for updated 2006 information measured in hits in Google blogs). Lingua franca, literally Frankish language in Italian, was originally a mixed language consisting largely of Italian plus a vocabulary drawn from Turkish, Persian, French, Greek and Arabic and used for communication throughout the Middle East. ... For the scientific and engineering discipline studying computer networks, see Computer networking. ... SourceForge is a collaborative revision control and software development management system. ... C is a general-purpose, block structured, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... C++ (pronounced see plus plus, IPA: ) is a general-purpose programming language with high-level and low-level capabilities. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... This article is about the corporation. ...

An occasionally voiced criticism of the Java language is that it evolves slowly, lacking some features which make fashionable programming patterns and methodologies easier.^{[citation needed]} Others point to C# and say that its designers are perhaps too quick to pander to current trends in programming - lacking focus and simplicity.^{[citation needed]} Java's designers seem to have taken a more conservative stand on adding major new features to their language syntax than other current languages, perhaps not wanting to tie the language too tightly with trends which may prove to be dead ends.

This trend may have been broken with the Java 5.0 release, which introduced several new major language features: a foreach construct, autoboxing, methods with variable number of parameters (varargs), enumerated types, generic types, and annotations. With the exception of Generics, C# included all these features from its beginning, some under different names.^[14] Proposals and specifications for the new features had been worked on in the Java community for considerable time before they were introduced. Indeed, some had been in gestation since before C#'s initial release (e.g., work on Generics formally began in May 1999^[15]) such was the Java community's conservatism at that time. For each (or foreach) is a computer language idiom for traversing items in a collection. ... In computer science, an object type (a. ... In computer programming, a variadic function is a function of variable arity; that is, one which can take different numbers of arguments. ... In computer programming, an enumerated type is a data type whose set of values is a finite list of identifiers chosen by the programmer. ... Generic programming is a style of computer programming where algorithms are written in an extended grammar and are made adaptable by specifying variable parts that are then somehow instantiated later by the compiler with respect to the base grammar. ... Annotation is extra information associated with a particular point in a document or other piece of information. ... May 1999 : January - February - March - April - May - June - July - August - September - October - November - December May 2 - Norman J. Sirnic and Karen Sirnic are murdered by Angel Maturino Resendiz in a parsonage in Weimar, Texas. ...

Problem-specific language additions to Java have been considered and, for now at least, rejected. This approach, along with a number of other new languages and technologies that address themselves specifically towards current programming trends, has sparked a renewed debate within the Java camp about the future direction of the Java language and whether its 'conservative evolution' is right.

Currently the debate is raging over the inclusion of closures^[16] and properties^[17] into the language syntax for Java 7. In computer science, a closure is a function that is evaluated in an environment containing one or more bound variables. ... In some object-oriented programming languages, a property is a special sort of class member, intermediate between a field (or data member) and a method. ...

C#

By contrast, C# is a relatively new language. Microsoft has studied existing languages such as Java and Delphi, and has changed some aspects of the language and runtime environment in response to perceived failures and difficulties with its predecessors. C# accommodates constructs more commonly found in languages such as C++, Delphi (designing which was Anders Hejlsberg's principal job when he was at Borland), and, in recent C# versions, borrows from dynamic scripting languages such as Ruby. C++ (pronounced see plus plus, IPA: ) is a general-purpose programming language with high-level and low-level capabilities. ... Delphi is the primary programming language of Borland Delphi. ... Anders Hejlsberg (born December 1960[1]) is a prominent Danish software engineer who co-designed several popular and commercially successful programming languages and development tools. ... Borland Software Corporation is a software company headquartered in Austin, Texas. ... Ruby is a reflective, object-oriented programming language. ...

C# has evolved rapidly to attempt to streamline development for problem-specific features. C# 3.0 adds SQL-like language integrated queries suited for querying data from collections, databases or XML documents. It however builds upon general-purpose language features; lambda expressions and extension methods features, that also allow such queries to be expressed and optimized for user types. SQL (IPA: or ), commonly expanded as Structured Query Language, is a computer language designed for the retrieval and management of data in relational database management systems, database schema creation and modification, and database object access control management. ... Language intergrated query (LINQ) is a Microsoft project that aims to add a native querying syntax to C# and VB.Net. ... In object-oriented programming, a collection class is any class that is capable of storing other objects. ... This article is about computing. ... The Extensible Markup Language (XML) is a general-purpose markup language. ... In computer science, the lambda calculus is a formal system designed to investigate function definition, function application, and recursion. ... // One of the features of C# 3. ...

Before creating C#, Microsoft implemented a modified Java environment, called J++, adding new features in a manner which was in direct contravention to the standards and conventions ensuring the platform neutrality which lies at the heart of Java. This violated the license agreement Microsoft had signed, requiring that standards and specifications be strictly adhered to in return for using the Java name and brand logos. Sun Microsystems sued, and won, thus preventing Microsoft from further production of J++. With the release of the .NET framework (and C#), the project was revived in the form of J#. Visual J++ (pronounced Jay Plus Plus) is Microsofts now discontinued implementation of the Java programming language. ... The J# (pronounced J-sharp) programming language is a transitional language for programmers of Suns Java and Microsofts J++ languages, so they may use their existing knowledge, and applications on Microsofts . ...

See also

• Comparison of C# and VB.NET
• Comparison of Java and C++
• Java programming language
• C#
• Comparison of the Java and .Net platforms

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References

1. ^ Maharry, Dan; Sundar Bandepalli (2004). "ASP.NET Developer's Cookbook" and "Learning C#". Book Reviews. .NET Developer's Journal. “Microsoft .NET is poised to become the next big thing to hit software development. C# (pronounced c sharp) ­ a hybrid of C++ and Java, with the simplicity of Visual Basic ­ is the new language for coding.”
2. ^ Generics in C#, Java, and C++
3. ^ InfoQ: Closures proposed for Java
4. ^ ^{a b} Java for Scientific Computation: Prospects and Problems
5. ^ JSR 13: Decimal Arithmetic Enhancement specifies enhancements to the BigDecimal type that were implemented in Java 5.0, to allow broader usage of the type.
6. ^ CLR Inside Out
7. ^ August 1998 Java News
8. ^ The Trouble with Checked Exceptions
9. ^ Why doesn't C# have exception specifications?
10. ^ O'Reilly, Tim (2006-08-02). Programming Language Trends. Radar. O'Reilly.
11. ^ Developer Use of AJAX Up 10%, Java Still the Leader Says Evans Data's Fall Survey. Java Industry News. JDJ (2006-11-30).
12. ^ Java history was made today!. JRoller (2005-11-24).
13. ^ Chakraborty, Angsuman (2006-07-19). Java Gains in Popularity. Taragana.
14. ^ Java 5 catches up with C#
15. ^ JSR 14: Add Generic Types To The JavaTM Programming Language
16. ^ Debate over closures for Java
17. ^ Property Support in Java, the Java Way

External links

• Contrasting C# and Java Syntax
• Java vs. C# - Code for Code Comparison
• Nine Language Performance Round-up
• Java and C-Sharp Compared
• MSDN: The C# Programming Language for Java Developers
• Standard ECMA-334 C# Language specification
• Java Language Specification (Sun)