I have been trying to get an automated system for the video game minecraft to work. I have to compile it myself, and after following the guide EXACTLY, I get this when running the build.xml with ANT. Below is the code and the error in it.
Buildfile: C:\Users\Arm\workspace\DarkBot\build.xml
init:
clean:
[delete] Deleting directory C:\Users\Arm\workspace\DarkBot\bin
compile:
[mkdir] Created dir: C:\Users\Arm\workspace\DarkBot\bin
BUILD FAILED
C:\Users\Arm\workspace\DarkBot\build.xml:21: Unable to find a javac compiler;
com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "C:\Program Files (x86)\jre1.8.0_25"
What am I doing wrong? Also I can assure that JAVA_HOME points to the correct area, as suggested in the error message.
JRE is not equal to JDK.
JRE stands for Java Runtime Environment, which is used to RUN Java programs.
JDK stands for Java Development Kit, which is used to COMPILE Java programs; it includes javac, the Java compiler.
Install JDK and points JAVA_HOME to correct location to resolve your issue.
Install JDK , JDK compiles your program and it has javac in bin folder like this "C:\Program Files\Java\jdk1.7.0_51\bin".
Set its path in Environment variables either in system variables "path" key or as "JAVA_HOME"
you can try Uninstalling and Re-installing already installed one.
All ant stuff will work fine except the javac task which needs the tools.jar, located in the /lib directory from the JDK, JRE is not sufficient in that case.
eclipse setting
Right Click build.xml ---> Build path ---> configure buildpath ---> select libraries tab
click "Add library" ---> double click on [jre system library ] ---> environments ---> installed jres ---> Add ---> standard vm
click on directory ---> Browse upto jdk [C:\Program Files\Java\jdk1.7.0_01]
finish
change the selection jre to jdk ---> click ok
If you can not find the path after testing on the command prompt and it says something like 'error java not found or it is not available from the internal or external .....' then follow the steps below:
Go to C:\Program Files\Java\jdk1.7.0_76\bin this shows the location of your java bin copy the path shown.
Go to Mycomputer > system properties > advanced settings> Click on Environmental Variables > (check this closesly... on the second section of the window where it says 'System Variables' scroll down the list till you find 'path' on the left)
click on the 'path' found from the list of system variables and click 'edit'.
Now paste your copied link in my case C:\Program Files\Java\jdk1.7.0_76\bin
Click Ok and go back to command prompt and test it. I hope this helps as mine is working now.
Related
So I've been trying to figure out how to run .java files because I was trying to run someone's program and I've been researching solutions for sooo long
cd "directory with file trying to run"
set path=C:\Program Files\Java\my-java-version-or-whatever\bin
javac Test.java (<-- name of file)
also tried
SET JAVA_HOME
and that worked and showed a path but when I did javac again it still didn't work. All help is much appreciated!!
And for some reason it just keeps saying that javac is not recognized.
Please install JDK on your machine and point the JAVA_HOME to the same.
Find JDK Installation Directory
Open the default installation path for the JDK:
There should be a subdirectory like:
C:\Program Files\Java\jdk1.8.0_191
Set the JAVA_HOME Variable
Once you have the JDK installation path:
Right-click the My Computer icon on your desktop and select Properties.
Click the Advanced tab, then click the Environment Variables button.
Under System Variables, click New.
Enter the variable name as JAVA_HOME.
Enter the variable value as the installation path for the Java Development Kit.
Click OK.
Click Apply Changes.
If you have just set your JAVA_HOME make sure you restart your command console.
I am trying to install Java in Windows 10 Home (64 bit). Like many tutorials point out, I downloaded the Java jdk setup file, executed it and once installed changed the Path in the Environment Variables. But for some reason, when I execute the command 'javac' it returns the not internal/external command error in Command Prompt but runs absolutely fine in Powershell. I tried to rectify this by uninstalling Java and reinstalling it very carefully, following all the steps but still this keeps on happening.
Also, during installation of Java, I lost the original value to my Path variable. Could this be causing the problem?
Edit : I was able to get the java command running in the command prompt but javac still won't work. I've already tried the methods suggested on other forums and this one but no luck so far.
See there is no problem with Java installation if you can find JDK(Java development kit) and JRE(Server Java runtime environment) in programme files in windows in a JAVA folder.
The main problem is with the environment variable declaration.
Go to environment variables and make a new path for that.
JAVA_HOME = "YOUR JDK & JRE INSTALLATION PATH"
And another one is
JAVA = "YOUR JDK & JRE INSTALLATION PATH"
Hope that help to you. After doing that if still there problem persisist just restart your PC and check again.
Just add your variable location up to /bin/
Refer to this :
https://www.windows-commandline.com/javac-not-recognized-internal-external-command/
Open file explorer
Right click computer then click properties
click advanced system settings
click environmental variables
click path (for me there was one in user variables for admin and another in system variables)
find the directory for javac (for me it was here C:\Program Files (x86)\Java\jdk1.8.0_191\bin)
so go back to file explorer and open program files x86
then open the java folder
then open the jdk folder
then open the bin folder
highlight the path in the search bar and copy it
click edit on path and paste into the path in the environmental variable for both(if you have more than one path)
If no path exists then create one in user variables
If there is any existing text place a semicolon ; between the text you pasted in there and the preexisting text.
close command prompt and reopen it.
type javac -version
the version info should be listed
This problem comes up with the directory of your command prompt.
check your PowerShell and command prompt default directory.
We can run command prompt as WinKey+R then type cmd, Hit the enter button then check our java version cmd javac -version.
I'm trying to set up Cordova. When I run cordova build android I receive the following error:
(node:6816) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 1): Failed to run "javac -version", make sure that you have a JDK installed.
You can get it from: http://www.oracle.com/technetwork/java/javase/downloads.
Your JAVA_HOME is invalid: C:\Program Files\Java\jdk1.8.0_161;C:\Program Files\Java\jdk1.8.0_161\bin
However I can run javac -version just fine.
C:\>javac -version
javac 1.8.0_161
I've tried to set JAVA_HOME in various ways: pointing to the root; pointing to the bin folder; set it as a User variable and also a System one; add %JAVA_HOME%\bin to Path (both for User and System) and so on.
I've checked several articles about this issue, and they say that if I'm able to use javac -version then that's supposed to indicate that my environmental variables are set correctly. Even if that's the case, Cordova still doesn't seem to recognize it.
Update
Following Stephen C's instructions, I've reset my variables, yet my error still persists. As you can see in the image I can call javac just fine, and both JAVA_HOME and Path seem to be set in the right way. (Note that actually it is %JAVA_HOME%\bin and not C:\Program Files\Java\jdk1.8.0_161\bin in the Path.)
I think you are confusing JAVA_HOME, PATH and CLASSPATH
The JAVA_HOME variable should be set to the name of a single directory. Not multiple directories with separators. The JAVA_HOME directory is the top directory of your JDK or JRE installation. Not the "bin" directory.
The PATH and CLASSPATH variables consist of a list of paths. For PATH the paths are pathnames for directories. For CLASSPATH the paths are pathnames for directories or JAR / ZIP files (or a particular kind of wildcard).
The PATH is where the shell searches for commands if you use a command name that is a simple name; e.g. java or javac.
`
The CLASSPATH is one of the ways that you can tell Java tools to look cor compiled classes to load, compile against, etcetera.
Your error message says this:
Your JAVA_HOME is invalid:
C:\Program Files\Java\jdk1.8.0_161;C:\Program Files\Java\jdk1.8.0_161\bin
This is wrong for two reasons:
JAVA_HOME should not be a path
C:\Program Files\Java\jdk1.8.0_161\bin is not a Java home. The Java home is C:\Program Files\Java\jdk1.8.0_161 .... probably.
The other thing you may have gotten wrong is that changes to environment variables do not necessarily propagate. For example, if you start a shell and then change an environment variable via the Windows GUI, the change may not propagate to the shell. You may need to exit the shell and restart it to pick up the new value.
If you are unsure, you can run (for example) echo %PATH% to see the current value of PATH in the current shell or script.
UPDATE
According to http://cordova.apache.org/docs/en/7.x/guide/platforms/android/index.html, you need to:
install Android Studio
set the ANDROID_HOME environment variable to the location of your Android SDK installation.
It is also recommended that you add the Android SDK's tools, tools/bin, and platform-tools directories to your PATH.
Remove java.dll from C:\Windows\System32 (if any).
I'm not sure but It may work correctly.
When I go to open eclipse, it gives me a run time error saying that the path to the JDK is not right.
I have no idea where to save the link so that i can get it to open
First Install Java on your pc: It should create Java Folder in C:\Program Files.
You have to set Classpath like this :
Set the CLASSPATH environment variable
(for **Windows NT/2000/XP**)
1. At the left bottom corner of your computer desktop, choose Start -> Setting -> Control Panel, and double-click System
2. On Microsoft Windows NT, select the Environment tab; on Microsoft Windows
2000/XP select the Advanced tab and then Environment Variables.
3. For either User variables or System variables, click New and in the popup window, enter Variable name as CLASSPATH (note that all letters should be capital), and the directory where your JDK is installed as the Variable value.
For example:
If your JDK is installed at: C:\jdk1.4.1_06
Put the following line as the value:
C:\jdk1.4.1_06\bin;C:\jdk1.4.1_06\jre\bin;.
The first is where the java compiler 'javac' is, the second is the java run time environment 'java' is, and the final '.' denotes your working directory, so that the compiler and jre will find where your programs are. To be safe, you may also want to append the above line to then end of your PATH variable. Use ';' as the separator.
Save the variables, test the setting by opening a DOS prompt, type in
echo %CLASSPATH%
If your environment variables are set correctly, you should see your settings.
Or, you can just type in
javac
java
If your PATH and CLASSPATH is correct, windows should recognize those commands.
You do NOT need to restart your computer when installing Java.
Check whether TextPad and Java SDK work on your computer
Download HelloWorld.java into your local drive. Be sure that filename is case sensetive in JAVA programming.
Start TextPad, and open this HelloWorld.java file.
Click menu "Tools" ---> "Compile Java" to compile java file.
Click menu "Tools" ---> "Run Java Application" to run this file.
If you see "Hello World" in a DOS PROMPT window, that means there is no problem with your TextPad to compile/run Java program. Congratulations. You can start your java programming now. If you see some errors when run Java program, please click here to get more information.
For a more comprehensive description on how to setup Java environment on Windows machinese, please refer to the Sun document at: http://java.sun.com/j2se/1.4.2/install-windows.html
For **windows 7**: Follow this link http://www.abodeqa.com/2012/08/11/how-to-set-path/
Then : Start Compatible eclipse (e.g :64bit eclipse on 64bit os).
In Eclipse, select Windows | Preferences
Click the + in front of Java or double-click Java (after the +)
Click Installed JREs
Under the Name column, double-click jre1.5.0_08.
Click the Add External Jars... button.
In the Jar Selection window, navigate to your workspace folder, and double-click the file cs15-1xx.library.
In the Edit JRE window, click OK
In the Installed JREs window, click OK
Terminate (X) the Welcome window
You can always get it back by selecting Help | Welcome
Terminate (X) the Eclipse window.
For more Details follow this : http://blog.ajduke.in/2013/04/28/setting-up-new-java-compiler-and-runtime-in-eclipse-ide/
You can specify the target JRE when launching eclipse by with the -vm command line argument (either through a shortcut or in the eclipse.ini file).
Command line syntax: eclipse -vm c:\jre\bin\javaw.exe
eclipse.ini file syntax (use 2 lines)
-vm
c:/jre/bin/javaw.exe
You can also copy a given version of the JRE under your eclipse installation directory.
Generally speaking I would really advise against adding %JAVA_HOME%/bin to your SYSTEM path. In my experience, this usually leads to many unexpected behaviors. Far better IMHO to set the JAVA_HOME and add its /bin directory to the PATH through scripts/command line/shortcuts/etc. and invoke those when needed.
I downloaded this Java JDK and installed it.
But when I go to the command prompt to check the version, it says it's not recognized.
Is anyone else experiencing this issue with the latest Java?
I might not have installed the right version. I need the java that works with grails
C:\>java
'java' is not recognized as an internal or external command,
operable program or batch file.
C:\>java -version
'java' is not recognized as an internal or external command,
operable program or batch file.
C:\>
when i do a search on my computer for java, it does not find anything
Windows 2k8 R2 server-
For both java [-option] or %JAVA_HOME% to work in the command line you need the following:
In Control Panel->System and Security->System->Advanced system setting->Advanced->Environment Variables->System Variables
Edit the Path variable and add a ";" after the last value and add the the path to the Java bin directory:
e.g.- C:\Progra~2\Java\jre6\bin\
Add the JAVA_HOME Variable with the value set to the path for the java executable:
e.g.- C:\Progra~2\Java\jre6\bin\java.exe
Press simultaneously the "windows" and "pause" buttons on your keyboard, this will bring up the System Preferences dialog.
In the Advanced tab, find Environment Variables.
Then, in the User (upper) section, create or update the following two variables :
JAVA_HOME = where you put your JDK, eg. C:/Java/SDK
PATH = %JAVA_HOME%/bin
Close the dialogs.
Then, in a new command-line console, try "javac -version" and see if it's detected.
It's important that you use a new console, because environment variables are read only when the console is launched.
Java is typically installed (on Windows) as C:\Program Files\Java\jdk<version>
That installation directory has a subdirectory bin which you need to append to your PATH environment variable via the control panel. Then, the commands like java, javac etc. will be available on the command line.
BTW, the same is true for Grails.
Is the -version flag not recognized, or is the "java" command not recognized? One way to test this is just to type 'java' by itself and run it and see what happens.
If the command is not recognized, make sure that the JDK's install path is in your windows PATH. If not, you won't be able to use any of the java executables from the command prompt. Here's another link that may help out.
You need to manually add the path to javac.exe and java.exe to your operating system path. The Java installation program doesn't do that for you.
You most likely don't have java.exe in your system's PATH variable.
For Linux:
check $PATH and $JAVA_HOME. You can configure it in /etc/environment
From console you can check it like:
$ echo $PATH
For Windows:
My Computer -> Properties -> Advanced -> Environment Variables
Check there PATH.
From console you can check it like:
echo %PATH%
You should have a Java icon in Windows Control Panel. Locate the Java tab and click the View button. That will show you the path to the Java executables.
Last but not least, make sure you have restarted the computer so changes in the PATH variable can take effect.
You installed the JDK. Isn't java.exe part of the JRE? Do you have that installed?
Maybe your system variables in the environment variables are not set properly. Follow the steps in the link below. Finally, make sure the path component in system variables has only one JDK path. Delete other JDK paths that you won't use.
https://docs.oracle.com/javase/tutorial/essential/environment/paths.html
You might have installed a previous or older version of Java so you can just uninstall it and directly download JDK from Java JDK
I was also facing the same issue but when I downloaded and installed the latest version the issue was resolved.
Also uninstall any other Java versions which may be present in the program files.
To get to know other versions which may be present in your computer use Windows File Explorer to go to:
Files > Windows C > Program Files > Java
All the JDK and JRE you have will be listed there. Uninstall any other Java versions other than what you installed. And then make sure you have set the path variable of the JDK.
For me, it was incorrect line in the PATH
(1) Check PATH: Type "Edit System Environment Variables" on the search -> System Properties -> Advance -> Environment Variables -> System variables -> Path
(2) On the list, mine was C:\Program Files (x86)\Common Files\Oracle\Java\javapath so I just add \ at the end (the exe files in the javapath folder)
OS: Windows 10 64 bit
IF you set the PATH and it's not showing up in cmd when you run %PATH%, try restarting your computer.