Can I Write A Java Template And Convert To C Sharp

Interoperability betwixt JVM & CLR

Abstract The real concept driving this article is to develop solutions using the .Internet or Java Framework that interoperate with heterogeneous systems or even mutually communicated with each other. The Coffee Virtual Machine (JVM) exposes the Java Native Interface (JNI) that allows other programs to command the JVM. For case, load classes, create instances, and run methods. This sample shows the amazing tactics of mingling both C# and Java code in i source code file and producing the desired results. Nowadays, the system works on multiple projects simultaneously and the corporating infrastructure is normally configured with a couple of platforms such every bit .NET, Java, and PHP to fulfill the developer's requirements. And so, it is skilful to interoperate or set upwardly advice across these technologies to save homo efforts and computer resources because one algorithm developed on the .NET platform could be packed as an API or DLL files and be consumed beyond diverse platforms.

Essential The aspirant is supposed to be convenient in both the Coffee and C# programming languages as well as having a deep agreement of the JVM and CLR internals. This operation requires the subsequent software to be installed every bit listed beneath.

Jni4net
Jdk
JVM
Eclipse (optional)
.Internet Framework
Visual Studio 2010 (optional)

Interoperability Interoperability enables advice, data substitution, or programme execution among diverse systems in a way that requires the user to have niggling sensation of the underlying operations of those systems. The programmers can get the advantage of the power of the Java platform by applying the JNI without having to abandon their investments in legacy code because the JNI is a core part of the JVM. Programmers can address interoperability issues in one case and expect their solution to work with all implementations of the Java platform. Do suspicions often occur in the listen of a developer, such every bit why is interoperability and so important? What kind of bug is information technology precisely addressing? To what extent is interoperability technology between Java and .Internet beneficial? Here, the subsequent advantages are outlined to justify interoperability as in the following:

Migrations: migration must be well planned and carefully executed when the system is updated or replaced and often involves moving an application a few parts at a fourth dimension. This fashion of dividing a system for migration purposes ofttimes creates a demand for interoperability because some parts that have been migrated yet might need to communicate with others that have not.
Reusability: about established companies have a number of legacy systems. By the term legacy, I mean applied science that'southward not been keenly developed today. For example, a organization located in the data eye that's withal in product but no longer offers a strategic reward to the company is a legacy system. A plan to motility these systems to a new platform might be a longer-term strategy. A solution that has the ability to interoperate with these systems has the potential to extend the life of these systems and more importantly, the noesis of the developers who piece of work with them.
Adoption: when organizations desire to deploy new technology such equally the .NET Framework, it's rare that they simply supplant an entire application or system. In many cases, a replacement is normally triggered by a airplane pilot project. Such a pilot tends to be a brusque-term project with an intent to prove that the technology can piece of work well with existing systems and applications. The ability for this pilot project to interoperate with existing production systems is imperative and in many cases, can often determine its success.

Coffee Native Interface (JNI)

Sometimes, a situation arises where Java or .NET lonely does not fit the needs of your awarding. While we can write and execute applications entirely in Java and the .Internet Framework independently. Programmers use the JNI to write native methods to handle those situations when an awarding cannot be written in Coffee and .Internet independently. The Java Native Interface framework is devised to enable Java code running in a Java Virtual Car (JVM) to phone call, and be chosen past, native applications and libraries written in other programming languages, for instance, .NET, C++, and assembly. JNI tin besides modify an existing application that is developed and executed nether the CLR to be accessible to Java applications. In unproblematic terms, we tin say that we can call .NET applications and libraries in Coffee and vice-versa using the JNI. Native lawmaking relatively runs faster than JVM code so such implementations can aid, to a dandy extent, in solving complicated and time-critical operations.

Coffee, native languages, and .Internet have their own data blazon infrastructure. During interoperability or communication of these diverse languages amidst each other, it is necessary to comply with a common data type scheme so that all participant languages can send messages between each other and follow the data type semantics. The post-obit table describes the primitive types in the Java programming linguistic communication and the corresponding types in the JNI.

Java Native Interface

The Java platform is implemented on top of a host platform. And then, it is necessary to allow Java applications to piece of work closely with other language'due south native code written so that the developer tin arrange the Java platform to build applications that were traditionally written in .Net and C++. The JNI is specially designed to interoperate or combine Java applications with the CLR or native code. The JNI typically offers two types of native code: native awarding and library. We can apply the JNI to write native methods that allow Coffee applications to call functions implemented in native libraries. Coffee applications are called native methods in the aforementioned way that they telephone call methods implemented in the Coffee programming linguistic communication.

Jni4net Framework

Sometimes circumstances need that Coffee and .NET technology send letters or communicate with each other in order to save human effort or reduce the programming glitches. Information technology is not necessary that a company infrastructure to cull J2EE or the .NET Framework particularly. An algorithm written in the Java language could exist consumed or manipulated in a .Internet Framework or vice-versa. Jni4net is a mechanism that allows a Java program to call a function in a C# program and a C# program to call a method in a Coffee program. The jni4net framework includes both .NET FCL and JDK core classes to maybe use a Reflection engineering implementation across the boundary.

Jni4net

And then, jni4net could be conceived as an API that is frequently used in Java or .NET engineering. Apart from that, this framework offers a couple of other functionalities such as garbage drove, automatic proxy generation, and inter-process communication. The jni4net framework also addresses the interoperability mechanisms similarly supported past other languages. This is, however, not designed for a specific implementation of the Coffee Virtual Machine. Rather, it is a native interface that can be supported past every implementation of the Java Virtual Machine.

Embedding Java code in C#

This section illustrates how to implant Coffee code into an existing CLR C# lawmaking. The subsequent Java sample code does some arbitrary mathematical calculations. This sample integrates Java code with C# code and justifies the means for interoperability by taking the input from C# code and passing that argument to Java code to do the improver performance. And then, the message communication is happening across the JVM and the CLR. That is ane of the virtually noticeable mechanisms of this sample.

Getting Started Outset of all download jni4net from the cyberspace that is in fact, an open-source production. The jni4net package contains a couple of DLL and jar files that shall portray the key office in cross-boundary communication across the JVM and CLR. The jni4net-0.viii.six.0-s-bin Cypher file has a lib folder that contains all the necessary library files as in the following:

Jni4net dll

Effigy: jni4net package files

Thereafter, create a Panel based C# awarding as jniDemo and add together a reference for jni4net.n-0.8.6.0.dll from the Solution Explorer as follows:

Jni4net demo

Figure: Adding a reference

Now, provide the entry of a jni4net parcel from the start of the source file in the using statement every bit net.sf.jni4net that provides the Coffee primitive classes access into the C# IDE.

using net.sf.jni4net;

Later, in the main method, telephone call the CreateJVM () methods that create a temporary Java Virtual Auto surroundings in gild to execute, interpret, or execute the Coffee code as in the following:

Bridge.CreateJVM( new BridgeSetup());

Thereafter, provide the arbitrary mathematical calculation implementation. We can access the Java form name by the coffee.lang namespace followed by the @ graphic symbol. Here discover one more point, we are getting user input from the control line argument, which is C# lawmaking indeed. So, we are mingling the implementation of C# with Java code as follows:

int a = java.lang.@Integer.parseInt(args[0]);
int b = java.lang.@Integer.parseInt(args[1]);

Finally, apply some C# lawmaking again as follows:

Console.WriteLine( "\n\nPress whatever key...." );
Panel.ReadLine();

So this sample showcases a perfect mix of source code paradigm of Java and .Net into one file. Here, the unabridged code of this implementation is equally in the following:

using Organisation;
using net.sf.jni4net;
namespace jniDemo
{
class Program
{
static void Main( string [] args)
{
Bridge.CreateJVM(new BridgeSetup());
java.lang.System.@out .println( "\due north\nWelcome Java! in .Internet world!\n" );
int a = java.lang.@Integer.parseInt(args[0]);
int b = java.lang.@Integer.parseInt(args[1]);
int p = a * b;
int q = a + b;
java.lang.Arrangement.@out .println(a + " * " + b + " = " + p);
java.lang.Organisation.@out .println(a + " + " + b + " = " + q);
Panel.WriteLine("\n\nPress any key...." );
Panel.ReadLine();
}
}
}

Later finishing the code, the important point to remember is to identify the jni4net.j-0.eight.half-dozen.0.jar file into the projection bind/debug folder. Otherwise, this project won't compile successfully.

Jni4net jar file

Effigy: placing jar file in the bin/debug folder

Finally, run the application from the command prompt and pass the integer type argument followed by the executable and notice the output.

run application command prompt

Figure: Java code calling from C# output

And then, it is no more wonder to execute Java code in the CLR. The jn4net framework makes it possible to mingle the source code of these languages and let them communicate with each other.

Embedding C# code in Java Nosotros have seen how to call Java classes and methods from the C# code earlier. Now, we shall do the opposite in this segment. And then, first, open the Eclipse IDE and create a new console-based application as a exam. Then, right-click on the test project from the package explorer and select Properties. Here go to the Coffee build path and select the libraries tab. Then add or import the jni4net.j-0.8.6.0.jar reference in order to show C# classes in Java source code as in the following:

Adding jar file

Figure: C# Adding jar file

Subsequently calculation the jar file, you tin find its reference entry into the package explorer as follows:

Package explorer

Figure: C# jar file reference in the Packet explorer

Information technology is now time to write the C# code in the Coffee source code file. However, first, import the C# course specification namespace as follows:

import net.sf.jni4net.*;
import system.*;

The post-obit sample just implements the logic of showing the environment variables and crucial information of the auto past employing the C# dictionary classes. As in the earlier sample, create a CLR virtual machine past the init() method that invokes the CLR to execute and run the C# code as in the post-obit:

Bridge.init();

Now put the C# code for the surroundings variable enumeration accessing in the while loops and display the data every bit follows:

Dictionary ev = arrangement.Environment.GetEnvironmentVariables();
IEnumerator keys = ev.getKeys().GetEnumerator();

Here, the unabridged code for this sample is given below.

import net.sf.jni4net.*;
import java.io.IOException;
import java.lang.Cord;
import organization.*;
import organization.Object;
import system.collections.IDictionary;
import system.collections.IEnumerator;
public class ajay
{
public static void principal(String[] args) throws IOException
{
Bridge.setVerbose(true );
Bridge.init();
Console.WriteLine("Hullo .Net world!\north\n" );
Dictionary ev = arrangement.Surround.GetEnvironmentVariables();
IEnumerator keys = ev.getKeys().GetEnumerator();
while (keys.MoveNext())
{
system.String k = (organization.Cord) keys.getCurrent();
Panel.Write(k);
Panel.Write(" = " );
Object value = ev.getItem(k);
String valueToString = value.toString();
Console.WriteLine(valueToString);
}
}
}

If nosotros desire to notice the behind-scenes processing related to the CLR virtual machine initialization, we can put this lawmaking before the init() method as in the following:

Bridge.setVerbose(truthful);

Enabling this option will prove everything related to the CLR and JVM just earlier the actual output equally follows:

CLR initialization

Figure: C# CLR initialization

Finally, debug and run this application. We will come across in the output the C# code enumerating all the environment variables of the organization via Coffee code as in the following:

calling from Java output

Figure: C# code calling from Coffee output

Concluding Note

This paper addressed the interoperability concept across Java and the .NET platform through the jni4net framework. We have heard that information technology is not possible to telephone call Coffee code from C# and vice-versa, only jni2net makes it possible by mixing both source code into a single executable file. This paper shows how to partially place both applied science's source code in a file and past invoking their corresponding virtual machines such equally the JVM and CLR. The important affair is that cross-boundary advice is possible, to properly configure the Coffee jar and a C# DLL file equally a reference in order to access these class library methods.