I'm having a issue with compiling java from my Command Prompt. At first it was saying javac isn't a recognised internal or external command and by reading up I see you need to change the path and thats what I did exactly to...
variable name: path
variable value:%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%path%;C:\Program Files\Java\jre7\bin;
I closed commpand prompt and attempted it again however the same issue came up.
I then tried echo %path% and the entire path line was echoed(entire line in terms of that variable value)
I also have tried "for %i in (javac.exe) do #echo %~$PATH:i" and that returns ECHO ON.
I'm quite stumped and confused now. My javafile is in and named main.java however I am trying to compile it whilst in the javawork folder in CMD
C:\Users\MYNAME\Documents\Javawork
Thanks,
You want the path to the JDK, not the JRE, in your system path. The JRE doesn't come with a compiler (javac).
To compile Java code you need to install the Java Development Kit (JDK) as javac.exe isn't included in the Java Runtime Environment (JRE).
The path should point to the bindirectory of the JDK.
Related
I am having som trouble with java, i have tried to fix my Path, but i am new to programming and don`t know what to do.
I have java installed at : C:\Program Files\Java\jdk1.8.0_92\bin
and at : C:\Program Files (x86)\Java\jdk1.8.0_91\bin
Here are some screenshots from my system variables: This pops up when i click on the system variable "Path", see the other picture.
System variables
When I am in cmd, and writing java -version or javac -version, I get this message:
"java/javac is not recognized as an internal or external command, operable program or batch file".
Have tried to restart cmd every time i have changed the path.
Try Setting separate variables for JDK & JRE
Also give a backslash "\" after bin in the case of both JDK & JRE
Hope this works
First go to this path to make sure that it is right.
second try to restart your cmd and try again.
This is a really stupid question I know, but I don't really know what I'm doing at the moment.
I downloaded some old source code online, I need to compile it and thankfully the previous developer created a few batch files that will compile all the files. However, I think they are using the wrong JRE because whenever I try to compile I get the error The system cannot find the path specified
The command being executed is this:
c:\jdk1.3.1_01\bin\javac -classpath c:\jes;c:\jdk1.3.1_01;c:\;c:\jdk1.3.1_01\jre\lib\rt.jar;c:\jdk1.3.1_01\lib\tools.jar Trait.java
So i'm assuming its the -classpath option, but I don't know where my current jdk/jre are. Any suggestions?
if you set java environment variable like this:
JAVA_HOME=C:\jdk1.5.0_06
PATH=%JAVA_HOME%\bin;%PATH%
CLASSPATH=.;%JAVA_HOME%\lib;%JAVA_HOME%\lib\tools.jar
you can use command:java -version to know the java version.
and user command: javac Trait.java to run this code.
I am trying to extract a jar file from Matlab code using javac from Library Compiler (java package).
I have set JAVA_HOME to:
C:\Program Files\Java\jdk1.7.0_71
and added to PATH:
C:\Program Files\Java\jdk1.7.0_71\bin.
When I enter java -version in my console, I get java version jdk1.7.0_71 and running javac -version shows jdk1.7.0_71.
However, it seems that matlab could not find javac, thus, I am not able to compile my .m code into a .jar file. When I tried to compile .m code I got the following:
Error: An error occurred while shelling out to javac (error code = -1).
Unable to build executable.
Executing command: ""C:\Program Files\Java\Java\jdk1.7.0_11\bin\javac" -verbose - classpath "...\MATLAB\R2014a\toolbox\javabuilder\jar\javabuilder.jar" -d "...\features_extraction\for_testing\classes" "...\features_extraction\for_testing\features_extraction\Class1.java" "...\features_extraction\for_testing\features_extraction\Features_extractionMCRFactory.java" "...\for_testing\features_extraction\Class1Remote.java" "...\for_testing\features_extraction\package-info.java""
This is the directory of my java bin folder and javac.exe exists : ...\Java\jdk1.7.0_71\bin\bin\javac? I found this link for compatibility between Java and Matlab2014a(which is my version) here. What should I check in order to correctly link Matlab to Java? A few days ago Matlab was working correctly with Java.
In my PATH I noticed the existence of the following path: C:\ProgramData\Oracle\Java\javapath in which there are three wrong shortcuts to java.exe, javac.exe, and javax.exe. When I type in matlab console getenv JAVA_HOME I am getting C:\Program Files\Java\jdk1.7.0_11 while when I wrote version -java I got: Java 1.7.0_11-b21 with Oracle Corporation Java HotSpot(TM) 64-Bit Server VM mixed mode. When I write javac in matlab console I am getting: Undefined function or variable 'javac'.
When I try to built C++ library I got a similar issue: Error: An error occurred while shelling out to mbuild (error code = -1).
Unable to build executable.
EDIT: Does the absence of the proper MCR counts in my case?
You said
getenv JAVA_HOME I am getting C:\Program Files\Java\jdk1.7.0_11 while when I wrote version -java I got: Java 1.7.0_11-b21
try to use setenv in MATLAB, doc here http://www.mathworks.com/help/matlab/ref/setenv.html
setenv('JAVA_HOME','C:\Program Files\Java\jdk1.7.0_71');
setenv('PATH','C:\Program Files\Java\jdk1.7.0_71\bin');
Following from the answers in this link
http://www.mathworks.com/matlabcentral/answers/131639-matlab-deploytool-not-working-fails-while-building
seems like you have to install JDK 1.7.0_11-b21, which is the one your MATLAB version is compatible with for compiling into jar. Also, after installing that specific version, you should modify the JAVA_HOME and PATH environment variables. Try that to see if it helps.
I was having a very similar problem with my installation.
I set the environment variable (press > type env > Enter) JAVA_HOME (under "User variables") to my JDK home directory (not the bin folder) without any trailing \ or ;.
The problem occurs because MATLAB cannot execute javac properly, however, in order to work out exactly what MATLAB is trying to execute (which is not working) we need to use the command window and not the Library Compiler.
It appears you have already done this but for completeness I will add the process here for others.
To find what MATLAB executes, click "Open log file" and copy the entire first line.
Paste the first line in the MATLAB command window and add -v to the end.
Press enter to run the command and note the "Executing command:" that is printed to the screen.
Once you have the "executing command" that MATLAB returns for you, check the first path in that command and make sure it matches your javac file.
In your original post you have done this and posted
C:\Program Files\Java\Java\jdk1.7.0_11\bin\javac
a path which contains \Java\Java, if this isn't a typo then it may be a problem as it is not the default Java installation path. You also say after that your installation is at
...\Java\jdk1.7.0_71\bin\bin\javac
which contains \bin\bin and is also not the default java bin install directory, perhaps another typo?
If the path to javac matches exactly you could try copying and pasting the "executing command" into your OS's command window (+R > cmd > Enter) and looking for errors. By doing this we can remove ourselves from the MATLAB installation and if errors still exist it likely has nothing to do with MATLAB.
To see if the same problem could be caused by other environment variables I removed every other path to a java installation (keeping JAVA_HOME) in my environment variables. MATLAB uses the absolute path to the java installation and so it was still able to compile with javac using only the JAVA_HOME environment variable.
Recently, when trying to compile java programs from the command prompt, I get this error:
Error: Cannot find or load main class com.sun.tools.javac.Main
I have the latest versions of the JDK and JRE, and I still get the error.
Here is what I type in the command line:
C:\Java_Source_Codes>javac hi.java
Can anyone help?
(Here is my java code)
public class hi{
public static void main(String[] args){
System.out.println("hello, world!");
}
}
You have a number of issues, Kumar mentioned the compilation issue, but that's not the immediate problem that's stopping you.
You have JAVA_HOME set to a Java Runtime environment, but are finding javac on the system PATH. When this happens, you can call javac from the command line, but when javac detects the JAVA_HOME environmental variable, it loads its libraries from a directory that doesn't include the "java tools", tools.jar. The contents of "java tools" includes the classes that implement the compiler.
You probably have JAVA_HOME set to something like /some/path/here/jre. Assuming that the jre directory is the embedded JRE shipped with your JDK, you probably should have set the JAVA_HOME to /some/path/here.
You need to have your PATH variable set up with a path to Java tools needed for compilation.
You need to have these folders in Path system variable.
D:\Program Files\Java\jdk1.6.0_32\jre;D:\Program Files\Java\jdk1.6.0_32\bin
Just replace D:\Program Files\Java with the folder you have installed Java on your computer.
Also, if you are using any other verion of JDK, replace jdk1.6.0_32 with your own.
This is due to some issue with your PATH.
Quick guess is you have multiple version of java on your PATH
Set the Path to the bin directory of the jdk in your system..
Try typing java -version on the cmd to see if your Java path is properly set.
Mine is..
C:\Program Files\Java\jdk1.7.0\bin
I had the similar problem but found a simple solution that might work in your case too.
My problem was I simply made a new folder in c directory to save my *.java files (like a test folder) and set my PATH to ...jdk\bin folder.
When I try to compile in cmd I got the same error main class not found.
So i went to environment variable and in user variable, where I saw my CLASSPATH pointing to same folder. So I changed my CLASSPATH to folder having my files in my case C:\test and the problem was solved.
Hope this helps.
What can I do when I keep receiving the error
'javac' is not recognized as an internal or external command, operable program or batch file
when I want to compile my jar or .class file?
Thanks
Make sure %JAVA_HOME%/bin is on your %PATH% (or $JAVA_HOME on the $PATH in *nix).
It means that it is not in your path. You have the following options:
1) Change to the directory where javac lives before calling it.
2) Use the full path to javac when making the call, e.g. C:\java\jdk1.6.0_12\bin\javac ...
3) Add the javac directory to the PATH environment variable
This just means that javac isn't in your PATH variable.
On Windows, you just have to add the folder that contains javac.exe to the PATH environment variable (Win+Pause/Break).
On Linux/Mac/Unix, just append that directory to $PATH in .bashrc or similar.
The error that you are seeing is generated by Windows, and isn't specific to Java. That error means that you typed a command and Windows could not find the command by that name.
The easiest way of rectifying the situation is to ensure that Java is properly installed in your system's PATH.
First, ensure that you have a JDK installed (and not just a JRE). Your next best bet is to add an environment variable called JAVA_HOME and point it at the base install directory for the version of Java that you installed.
Next, modify your PATH environment variable by prepending the string %JAVA_HOME%\bin; to whatever is already in your PATH. If you look at the contents of that directory, you will see that javac is in there (along with a number of other Java development tools).
You have to install JDK (which includes javac compiler) and ensure that it's in the path. See http://java.sun.com/javase/downloads/index.jsp
Common Error Messages from SUN Tutorial page
Step 4 (Update the PATH variable) of the JDK installation instructions explains what you should do to make it so that you can just type javac in the command prompt window.
The link below gives a step by step explanation on how to set up java_home and path variables.
JAVA_HOME setup
Even if I had
JDK installed
JAVA_HOME defined
%JAVA_HOME%\bin present in my %PATH%
I still had this error. I resolved it by eliminating the JRE from my path variable. It was put before JAVA_HOME, has no javac. It seems Windows can't find javac in JAVA_HOME\bin in this case.
For Windows
Control Panel > System...Then click Advanced System Setting (left pane)...then popup window will open...then click Environment Variables...Then another window will open...click New and add enter information below
Variable name: PATH
Variable value: C:\Program Files\Java\jdk1.7.0_45\bin [*make sure this is the right path for you]
Then it should work
Check whether you have JDK installed; if not installed, Install
If JDK is installed, navigate into the bin folder of the installation, and try to execute javac.
If javac executes, proceed (+:
If javac does not execute, check your system path, and java path, and return to 2 above!