If you have a small program, you can run jar file and it will work fine. But if you convert jar file into exe, you still need java to run your exe file, so what's the difference between them and why do some people convert jar to exe?
An EXE is, ostensibly, an executable program that launches the local java to execute the bundle classes.
As you may know, on your computer you can associate certain file extensions with local programs. For example, .doc files with your word processor.
Similarly, .jar files can be associated with Java, so that Java can execute them. The jar file is considered "stand alone" if it has all of the necessary classes bundled within it, and a proper manifest pointing to the startup class.
So, by associating .jar with Java, clicking on it in your environment will launch Java with the given jar file.
An EXE doesn't need that association. It find java on its own with it's own launcher.
The next step is that you can actually bundle the JRE in to an EXE, so you don't even need to have the user install Java as a pre-requisite. But that's a different process.
People commonly use Java executable wrappers for two reasons - 1. to simply deployment for environments without a JVM, and 2. To make sure the exact Java runtime used for developing the application gets used to run the JAR. However, the practice is not that much widespread.
Java archive or jar is an archive of compiled java byte code and resources which can be run on a java virtual machine. ".exe" is a windows extension for directly executable code mostly used by installers or programs that do not need to be installed. I think your "people" are talking about installers.
An Exe file is an executable file that can be executed in Microsoft OS environment.
Jar file is container of Java Class files, including other resources related to the project. Jar file can be executed only if Java run time environment.
The JavaTM Archive (JAR) file format enables you to bundle multiple files into a single archive file.
The .class files compiled from java files, can not be launched directly. That is why it is needed to be converted to exe before it can run in a windows environment.The usual way to start a java program by batch file is not a convenient way. So inorder to avoid this difficulty we need to convert jar files into exe file.
Also converting it to exe. enables the program to run by simple double click on the program, instead of having to compile it with an IDE or through the JVM.
All that the exe will do is to start a jvm with your app, something like this: "java -jar app.jar".
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How can I convert my Java program to an .exe file?
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Is there a way to create exe files or binaries in java? I've been only able to create java.class files after compiling the code, but I was wondering whether it is possible to create a normal program in a binary or a exe format that I could run without using command java File every time I want to run a program.
The suggested Executable jar files still require a java interpreter to be installed on the system. And as mentioned above, compiling directly into a Windows Executable looses platform independence. Yet it may be desireable to get a more native look and feel during application installation.
For this Oracle/the Java community created JPackage. It wraps your application together with the required JVM such that the whole package can be treated like a native application - regardless whether you want to run on Linux, MacOS or Windows.
You can package all the class files into a .jar file. This .jar file is executable by running java -jar <file>.jar, but most operating systems will allow you, when Java is installed, to double click on the jar file and execute it in this way.
Most build systems (such as maven and gradle) will make it easy for you to create such a file. If you have external dependencies (other jar files), you will need to create a "fat jar" that also includes those dependencies; there are plugins for those build systems to create fat jars.
You can use Launch4J to make an exe file, here you can find more info - https://youtu.be/jPKxqc8Zg-0
Java programs can be compiled into an .exe then someone can click on this .exe icon and run the app. My questions are:
Is that the only way a java program can be compiled and ran?
Is it possible to just write a class.java file, put this file on the
server, and expect it to "start working" without any kind of exe?
Are there other ways to compile java programs other than creating an
.exe or .apk file (Android)?
java class is compiled to form a .jar file and not an .exe file
A Jar file is essentially a collection of files (mostly archives of java classes) in one file, similar to a ZIP file. A Jar file facilitates the packaging of applications into one file. In addition to the Java class files and resources, a Jar file can contain a META-INF directory. The most important file in this directory is manifest.mf. It is used to define extension and package related data. The Main-Class: classname in the manifest file specifies the class that gets executed first.
A way I run text-based java programs is I make it into a .jar and then excecute it in CMD using java -jar nameOfJar.jar
Java applications are usually distributed as runnable jar packages, not exe where all java files are compiled into class files. You must consider that exe files are executable on Windows platform, but not in *nix, Solaris, etc.
So you can create .jar file. It runs on every platform which have installed JRE.
For android, you can create .apk file and that is it. Not an exe file!
Java programs are compiled to .class files that run on a Java Virtual Machine. The way to execute a Java Virtual Machine depends on the Operative System you are using.
Also .class files can be packaged on .jar, .war or .ear files.
At first, JAVA programs are not compiled to .EXE, they are compiled to .CLASS files which can be packaged into a .JAR files. You can simply distribute the .JAR files which can be directly executed when the system has JAVA Runtime installed.
Also please note that .EXE files are Windows Executables and cannot be run under other operating system environments but there are tools that convert .JAR files to .EXE files such as JSmooth and Launch4J.
I finished a small program. What is the standard file type for the final application written with Java, so it can be run on any computer, easily and without any computer knowledge?
I've been told it's JAR, but Eclipse for example is an .exe file.
What's the standard file type for big, normal applications in Java?
Are most applications distributed in JAR, or rather in .exe or something else?
Serious desktop applications are packaged with platform-specific launchers, which are not written in Java. The launcher must first find out how to run the JVM installed on the system, and then pass it either the path to the executable JAR to run, or the complete classpath along with the name of the main class.
In other words, "it's complicated".
Most desktop applications are distributed using .jar files. A .exe is windows-specific, and non-portable across different operating systems. It's easy to find installers (or "launchers") that will simplify the distribution of a Java program in other platforms, but anyway you'll find that .jar files are the usual packaging mechanism.
If you have a small, simple Java program the easiest approach to distribute it would be to pack it in a .jar, making sure to make it executable. And remember, the computer where your code is expected to run must have installed some version of Java, be it JRE or JDK.
Desktop java applications are usually distributed as jar files.
JRE can launch a runnable jar file using -jar param.
You have one of several options:
1 - Create an executable jar file. By providing information in a manifest within the jar file users can simply execute the jar file by however system-dependent means exist for their OS.
2 - Write a batch file or shell script to invoke the JRE against your jar file (and specify command line parameters for, eg: the main class, the classpath, JVM options, etc.)
3 - Use a tool like jexepack or jsmooth to wrap your Java code within a native executable. I've only ever used these to create Windows binaries - there may be other options for other platforms but shell scripts are typically easier to work with here.
I have exe file called Myapp.exe. Now I want to convert .exe to jar file. That jar file should also work in NON JAVA system. I don't have any idea to implement it. Can anyone please suggest me how to do it?
Direct conversion not available !!!
because they are in entirely different platforms.
Meeting your requirements is impossible for two reasons.
1) You cannot change an EXE to a JAR file.
2) You cannot run a JAR file on a system that doesn't have Java installed.
If you want to run something on a (Windows) system with no Java installation, it needs to be an EXE ... or something else that doesn't require Java.
(It might help if you explained why you think you need to do this. Perhaps there is an alternative set of requirements that are not impossible to meet.)
why i am doing all those stubs is for making my jar has to work in java not installed system.
It needs to be an EXE then!
I have an jar.It is working fine in java installed system.My task is to Bundle jre inside jar(Not along with jar(i.e we can put jre and jar in same folder to run a jar as given in following url mindfiresolutions.com/… ))Because i have to give jar file only to client,in such a way that they can use this Myapp.jar in non java system also.But,i don't know how to bundle jre inside jar.I Don't how to run jre inside jar?
Ermm ...
Is it possible?
No. You cannot embed a JRE inside a JAR file in any way that would allow it (the JAR file) to run your Java code without first installing Java. (And installing Java would defeat the purpose of embedding the JRE ... of course.)
But what you can do is create an EXE file which has a JRE and a JAR embedded in it. And there are tools for doing this. Here's the canonical Question on how to do it:
How can I convert my Java program to an .exe file?
I think you need to read the Oracle documentation on what a JAR file really is, and how Java programs are normally executed. That will help you understand what is feasible ... and what is nonsensical.
I am using JNI to wrap a few native functions in a closed-source PDF library. It has an dependent fonts directory which must be in a subfolder of the calling application's directory. In my experience, it is standard to seek based on the current working directory. Thus, the problem.
When loading the JNI code into a Java application, the current working directory is correct. However, the calling application's directory is java.exe's bin directory. I have verified that putting the dependent fonts folder in C:\Program Files (x86)\Java\jre6\bin folder works as expected.
The library seems to be using a C++ GetCommandLine() call, or something similar to determine where the fonts directory should be. Obviously, this is an unacceptable solution.
I'd like to avoid calling an external EXE. But the only workarounds that I've come up with are:
Compile an EXE, place in Java project directory, and use Java's Runtime.exec() to execute. (this does work)
Make JNI code launch a separate process which does the same as above (gains nothing but more complexity)
Any ideas on how I can circumvent this problem? When Java applications are compiled as a runnable JAR, is the resultant command line still the JRE's C:\Program Files\...java.exe?
A Java executable maker can create an executable *.exe from your Java application without any native coding or compiling. You can put that executable, the jar files, the fonts and other application dependencies into a single install directory.
Exe4j is one of the executable makers that will support this, for Windows. It does not require any assumptions about the current working directory. This is important in the frequent case where you have no control over what the working directory is when the application is launched.