What is the home directory for JDK? - java

I am having a problem in selecting home directory for JDK. Even though I have selected the following path: "C:\Program Files (x86)\Java\jre1.8.0_91", it keeps showing the error: "The selected directory is not a valid home for JDK". My java folder has two folders- bin and lib.
Window for selecting home directory
Kindly help me in selecting home directory.
Thank you!

You have currently located a JRE, or Java Runtime Environment. That does indeed contain a java executable and can launch JVMs, but it's not made for development, rather more as a "Java client". For example if you look into it's /bin folder, you won't find the javac executable needed to compile.
What you need is a JDK, or Java Development Toolkit. It contains all the JRE contains, with additional tools for development. You can find it for download on the Oracle website.

Your home directory will jdk not jre. If your jdk is installed properly then there will be a jdk folder. Try setting C:\Program Files (x86)\Java\jdk1.8.0_91\bin

Your home directory for JDK would be "C:\Program Files (x86)\Java\jre1.8.0_91\bin"

try this on windows to know the home of your jdk
c:\> for %i in (java.exe) do #echo. %~$PATH:i

Related

Trying to have Eclipse recognize jdk1.8, but I cannot find the folder

I'm using linux mint 19.3 and eclipse 2020-06, and I'm trying to get eclipse to recognize java 8 jre. The jre directory that I want to use is located at
/usr/lib/jvm/jdk1.8.0_251/
as shown in this pic.
So in eclipse, I go to
Window > Preferences > Java > Installed JREs
then I click
Add > Standard VM > Next
Now I am where the picture shows and I click Directory
Ok so here is the part that is confusing me. I navigate to /usr/lib using the eclipse directory tool, but there is no jvm directory.
Also, this /usr/lib directory seems very different; it's missing a bunch of things.
This is how the directory looks when I access it using the regular file manager
It almost seems like I'm accessing some other drive, but that can't be... because I have only one drive.
Any thoughts?

No Java folder located in Library despite JDK installation

Currently running OSX El Capitan on a recently set up computer. I'm trying to set up Java's unlimited crypto policy which requires me to modify some files within my current jre, but I can't find the Java folder that is supposed to be located within Library.
I've run /usr/libexec/java_home which shows me /Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk/Contents/Home however within my Library folder, there is no Java folder, even when I try and navigate through terminal it says Java folder doesn't exist. After trying to reinstall JDK 1.8, still no luck and I'm out of ideas.
This is not the Library folder in your home directory, this is the Library folder in the root file system on your main disk.
So in Terminal the command
cd /Library/Java/JavaVirtualMachines/jdk1.8.0_91.jdk
should work.
For different releases of Java replace jdk1.8.0_91.jdk with the appropriate release.
To list what is in the directory use:
ls /Library/Java/JavaVirtualMachines
Go to Macintosh HD/Library/Java
not to username/Library

JMF and Netbeans

I have installed the JMF for windows (jmf-2_1_1e-windows-i586.exe) from the following link:
http://www.oracle.com/technetwork/java/javasebusiness/downloads/java-archive-downloads-java-client-419417.html#7372-jmf-2.1.1e-oth-JPR
but when I double click on the executable file it unpacked to:
C:\Users...\TEMP
I don't know how to solve this problem.
I need to add the jar files to Netbeans.
Any help would be appreciated.
During installation the JMF-2.1.1, you can specify destination folder where you want to install the JMF:
Change the destination folder and install it either to
C:\Program Files\JMF (for 64 bit JMF)
or
C:\Program Files(*86)\JMF (for 32 bit JMF)
location according to system requirements.
After the installation, you can find your jar files at location:
C:\Program Files (x86)\JMF2.1.1e\lib.
You can add your jar files(customizer.jar, jmf.jar, mediaplayer.jar, multiplayer.jar) by choosing the Add jar option under Libraries section in NetBeans.
I have installed JMF with Netbeans by installing the zip folder cross-platform java from the following link:
http://www.oracle.com/technetwork/java/javasebusiness/downloads/java-archive-downloads-java-client-419417.html#7372-jmf-2.1.1e-oth-JPR
and at NetBeans Project, I added to the project library the following .jar files:
customizer.jar
jmf.jar
mediaplayer.jar
multiplayer.jar
I hope this will help.

How to open/run .jar file (double-click not working)?

I can't open or run my .jar file.
I just installed java, but I tried to open the .jar with other programs first, so the double-click defaults to something else and I can't change it back.
java -jar myfile.jar`
Above command returns:
'java' is not recognized as an internal or external command, operable program or batch file.
Is there a way I can still open/run this?
e: OS is Windows 8.
Also, I downloaded the .jar file; didn't create it myself (if that's relevant)
Not sure if it contains an executable (but I think it does).
you can use the command prompt:
javaw.exe -jar yourfile.jar
Hope it works for you.
There are two different types of Java to download: The JDK, which is used to write Java programs, and the RE (runtime environment), which is used to actually run Java programs. Are you sure that you installed the RE instead of the SDK?
Use cmd prompt and type
java -jar exapmple.jar
To run your jar file.
for more information refer to this link it describes how to properly open the jar file.
https://superuser.com/questions/745112/how-do-i-run-a-jar-file-without-installing-java
You may have several JDKs installed in your PC. Some older JDK installers also copy some java files such as java.exe, javaw.exe into C:\Windows\System32 folder.
I had a similar issue, and searched the internet for a solution and none of the suggestions didn’t open by double clicking the .jar file.
In my case the reason is I have multiple JDK & JRE versions installed on my computer. Since I am a software developer working with several different versions for different clients I need to use multiple JDKs in my PC (Windows 10 Pro). So I do not want to change the system variables (i.e. JAVA_HOME, JRE_HOME or PATH), instead I use command prompt to run java in user process whenever I wanted to use a different version.
When installing JDK it registers the .jar file association with latest version we installed in the PC. If you right click on the .jar icon and select properties, it will show that file opens with “Java(TM) Platform SE Binary”. If we look at the registry key: HKEY_CLASSES_ROOT\jarfile\shell\open\command, it will point to latest JDK version.
It is not a good idea (sometimes annoying) to change the registry key every time I want to run an app build from a different version.
So in my situation it is impossible to just double click the .jar file to execute it. But instead I found a work around solution myself.
Scenario:
Multiple JDKs (1.7, 1.8, 9.0, 10.0, 11.0, and 12.0)are installed in the PC, so the latest installed was 12.0.
Problem
Want to double click an executable .jar developed using JDK 1.8 and didn’t work
This is my work around solution:
Create a shortcut for the .jar file that you want to open.
Right click the shortcut icon and select properties -> Shortcut tab
Change the text in the target (for example "D:\Dev\JavaApp1.8.jar")
To
"C:\Program Files\Java\jdk1.8.0\bin\javaw.exe" -jar
"D:\Dev\JavaApp1.8.jar"
Then click ok Double click the shortcut.
It should now open the app.
I was having this same issue for both Windows 8 and Windows Server 2012 configurations.
I had installed the latest version of JDK Java 7 and had set my **JAVA_HOME**system env variable to the jre folder: *C:\Program Files (x86)\Java\jre7*
I also added the bin folder to my **Path** system env variable: *%JAVA_HOME%\bin*
But I was still having problems with double clicking the executable jar files. I found another system env variable OPENDS_JAVA_ARGS that can be used to set the optional properties for javaw.exe. So I added this variable and set it to: -jar
Now I am able to run the executable jar files when double clicking them.
In cmd you can use the following:
c:\your directory\your folder\build>java -jar yourFile.jar
However, you need to create you .jar file on your project if you use Netbeans. How just go to Run ->Clean and Build Project(your project name)
Also make sure you project properties Build->Packing has a yourFile.jar
and check Build JAR after Compiling
check Copy Depentent Libraries
Warning: Make sure your Environmental variables for Java are properly set.
Old way to compile and run a Java File from the command prompt (cmd)
Compiling: c:\>javac Myclass.java
Running: c:\>java com.myPackage.Myclass
I hope this info help.
Go to your java directory,
Copy this path
C:\Program Files\Java\jdk1.8.0_40\bin
Right click on my computer , click properties, then go to "Advanced system settings"
click , Environment variables.
go to "System variables" table, find an entry named "path".
Double click it and go to the end, put a semicolon and paste your path, apply and ok.
It should run now.
first of all, we have to make sure that you have downloaded and installed the JDK.
In order to download it click on the following link
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
(Do not forget to check "Accept License Agreement", before you choose the version you want to download)
For Windows OS 32-Bit (x86) choose "jdk-8u77-windows-i586.exe"
For Windows OS 64-Bit (x64) choose "jdk-8u77-windows-x64.exe"
Install the file that is going to be downloaded. During the installation, pay attention, because you have to keep the installation path.
When you have done so, the last thing to do, is to define two "Environment Variables".
The first "Environmental Variable" name should be:
JAVA_HOME
and its value should be the installation path
(for example: C:\Program Files\Java\jdk1.8.0_77)
The second "Environmental Variable" name should be:
JRE_HOME and its value should be the installation path
(for example C:\Program Files\Java\jre8)
As soon as you have defined the Environment Variables, you can go to command prompt (cdm) and run from every path your preferred "java.exe" commands. Your command line can now recognize your "java.exe" commands.
:)
P.S.: In order to define "Environment Variable", make a right click on "This PC" and select "properties" from the menu. Then the "System" window will appear and you have to click on "Advanced system settings". As a consequence "System properties" window shows. Select the "Advanced" tab and click on "Environment Variables" button. You can now define the aforementioned variables and you're done
You must create a manifest file and specify your class that has the main method. you can build your jar file with manifest file as a parameter.
jar cfm MyJar.jar Manifest.txt MyPackage/*.class
Manifest-Version: 1.0
Archiver-Version: Plexus Archiver
Created-By: Apache Maven
Built-By: Cakes
Build-Jdk: 1.6.0_04
Main-Class: com.foo.App
An easy way to execute .jar files is to create a batch file.
Let's say you placed your jar file on your Desktop;
#echo OFF
java -jar C:\Users\YourName\Desktop\myjar.jar
Copy this code to a .txt file, modify "YourName" and save as "myjar.bat". Then whenever you double click, the jar file will be executed.
Hope this helps.
Short trick: after I only REMOVED SPACES from names of the folders, where the .jar file was, double-clicked worked and the file executed.
In Netbeans please delete current you create the jar file and on the project explore of Netbeans please clean and build 2 or 3 times and right the project folder in project explore and build the jar file.
I had this problem a while back and the solution was really easy.
Just uninstall the current version of Java, download an older one, then uninstall the older and install the latest again.
For example: Java 8 Update 73 current install Java 7 Update 95.
How it works: Java's registry keys were messed up, and when you install the older version they get fixed.
If the intention of the question is to view the contents of the JAR file, then the following java command would help.. (provided, JDK location is added to the environment variables.)
Windows Command prompt> jar tvf yourJarFile.jar
Example:
jar tvf log4j-extras-1.2.17.jar
Reference: http://docs.oracle.com/javase/tutorial/deployment/jar/view.html
I downloaded the latest JDK 7u10. Once you do that, try running your jar, It should execute.

JSmooth question on bundling a JRE

I'm trying to bundle a JRE with my jar file so that I can run my application on any windows computer, regardless of if it has Java or not. The jsmooth manual says:
For the option to work correctly, you have to put a JRE in a directory near the EXE (generally in a subdirectory called "jre" or whatever). Once the exe is generated, it will FIRST try to locate the JRE at the location mentioned. If it can't be found there, then it will fallback in the normal jre look-up mode (search for a jre or a jdk in the Windows registry or in commonly-used environment variables). There is no JVM-version check when using a bundled JRE, as the packager is supposed to bundle a suitable JVM for the application.
Does this mean that the jre subfolder should be included in the jar, be its own separate jar, or put in the folder that comes along with the exe? If it is supposed to be in a folder with the exe, how can I specify the relative path to the jre subfolder?
My directories are as follows:
setup/
-jre/
-myprogram.exe
I tried using ..\jre, .\jre, ..\setup\jre in the GUI screen, but none of them worked.
Any ideas or leads would be greatly appreciated. Thanks so much!
EDIT: when I tried jre (and ..\jre I think), I got the following error message from windows when I tried running it "MyProgram.exe has stopped running." When I look at the problem details, it says APPCRASH and the fault module name is jvm.dll
just put the "jre" folder next to the exe, and write "jre" (without quotes) in the GUI of jsmooth
As an alternative, I would suggest using the mature open source project, NSIS. You could write an installer that would download and install the JRE, and then create shortcuts to run your program.
Here are some useful links:
http://nsis.sourceforge.net/Simple_Java_Runtime_Download_Script
http://nsis.sourceforge.net/Java_Launcher
Have you tried Launch4J (http://launch4j.sourceforge.net/), we switched from JSmooth to this a while ago, as it was more up to date and had more features.
But, put the jre folder in the same folder as the .exe, then use jre\ as the path to it. You'll need to make sure the working folder of the .exe is the installation folder though. And make sure you have a full JRE in the jre folder.

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