I am trying to compile and a sample Helloworld.java file.
I have my jdk installed in C:\Program Files\jdk1.7\bin.
And I have my Helloworld.java in C:\Helloworld.java
I am actually a novice in both powershell and java.
I got some examples from web regarding this but many of them advice to run it like this:
java.exe -classpath $Env:CLASSPATH C:\Helloworld.java
But when I give this in powershell I get an error called 'CLASSPATH' is not defined even after adding it in env variables.
And when I try to compile the code with the following syntax:
$javac C:\Helloworld.java I get an error "javac is not recognised as a token".
So, I am literally lost in this topic . Any step by step procedure to run java programs using powershell for dummies like me will be greatly appreciated.
Setup environment variables in your system.
set JAVA_HOME to C:\Program Files\jdk1.7
add to PATH variable the string %JAVA_HOME%\bin
open new cmd session.
navigate your java source folder.
use javac to compile your java files.
UPDATE:
also if you are experiencing difficulities upon launching an executable via PowerShell check this Microsoft TechNet article
The variables you speak of do not exist in PowerShell as you name them.
The correct variable names are
$Env:JAVA_HOME: C:\jdk1.6.0;
$Env:PATH: C:\jdk1.6.0\bin;.;
$Env:CLASSPATH: C:\jdk1.6.0\lib;.;
As they all must be defined in the ENV: PSDrive
To answer it in a much simpler way , its the path problem .
You probably not have set env variables that's it.
This is how you should set it:
JAVA_HOME: C:\jdk1.6.0;
PATH: C:\jdk1.6.0\bin;.;
CLASSPATH: C:\jdk1.6.0\lib;.;
And later if you open a cmd prompt and type java -version , if you are able to see the java installed version then you are good to go.
Related
I have to convert my Matlab algorithm in Java. For this I'm using matlab builder ja toolbox, after following all the necessary steps, the build fails and this error is displayed:
'javac' is not recognized as an internal or external command, operable program or batch file. Error: An error occurred while shelling out to javac (error code = 1). Unable to build executable.
When typing java -version in the matlab command line, this is what i get:
Java 1.6.0_12-b04 with Sun Microsystems Inc. Java HotSpot(TM) Client VM mixed mode
It means I should have this compiler of java installed on my computer, only then the matlab builder ja works. I'm new to Java, I'm not sure what compiler I should be looking for.
First make sure you have installed jdk and jre, both are installed with the java software development kit. The installation folder is typically C:\Program Files\Java.
Now go to Computer > Properties > Advanced system settings in the advanced tab click on Environment Variables
In System variables find the variable named Path, in the value of Path you will find a java path like C:\ProgramData\Oracle\Java\javapath, just change it to C:\Program Files\Java\jdk1.x.x_x\bin.
Hope that helps.
If you want javac (the compiler), you'll need to download the Java Development Kit (JDK), not just the Java Runtime Environment (JRE). Note that the JDK includes a JRE.
This tutorial give instructions to install JDK to your computer.
You need to make sure that Java SDK is installed and also PATH is set properly so that windows would be able to know where the executable is. Detailed steps on how to debug this issue is explained here: http://www.windows-commandline.com/javac-not-recognized-internal-external-command/
To solve the aforementioned problem follow the mentioned steps:
1) Copy the address location of your Java\jdk\bin folder usually installed in your C: drive. It should look something like this:
C:\Program Files (x86)\Java\jdk1.8.0_65\bin
2) Right click on My Computer-->Properties-->Change settings-->
Advanced-->Environment Variables.. -->New..
3) Now,
Set Variable name: PATH
Variable value: C:\Program Files (x86)\Java\jdk1.8.0_65\bin
4) Press OK, re-open your cmd and compile your program.
Hopefully it worked!
Path is defined as the filename. Ex, C://aklsej;dlfkj/blahblah
You will need to specify the full path in the system control panel, advanced system settings, edit variables, edit path, put a semicolon after the last entry and don't delete anything, and then add the full path wherever you installed java to.
to make this easy, do a search for javac in the search panel and then just add the full path to the environmental variables from there.
Set Following Environment Variables
It will works
JAVA_HOME=C:\Program Files\Java\jdk1.7.0_09
set PATH=%JAVA_HOME%\bin
Download Java from given link according to your requirements.
http://www.oracle.com/technetwork/java/javase/downloads/index.html
then follow below steps:
Step-1 : Right Click on MyComputer and click on properties .
Step 2 : Click on Advanced tab
Step 3 : Click on Environment Variables
Step 4 : Create a new class path for JAVA_HOME
Step 5 : Enter the Variable name as JAVA_HOME and the value to your jdk bin path ie c:\Programfiles\Java\jdk-1.6\bin and
NOTE Make sure u start with .; in the Value so that it doesn't corrupt the other environment variables which is already set.
Step 6 : Follow the Above step and edit the Path in System Variables add the following ;c:\Programfiles\Java\jdk-1.6\bin in the value column.
Step 7 :Your are done setting up your environment variables for your Java , In order to test it go to command prompt and type
java
who will get a list of help doc
In order make sure whether compiler is setup Type in cmd
javac
who will get a list related to javac
Hope this Helps !
If you receive this error, Windows cannot find the compiler (javac).
Here's one way to tell Windows where to find javac. Suppose you installed the JDK in C:\jdk1.8.0. At the prompt you would type the following command and press Enter:
C:\jdk1.8.0\bin\javac HelloWorld.java
If you choose this option, you'll have to precede your javac and java commands with C:\jdk1.8.0\bin\ each time you compile or run a program. To avoid this extra typing, consult the lecture "Creating a Hello World application" in this website
Class names, 'HelloWorld', are only accepted if annotation processing is explicitly requested
If you receive this error, you forgot to include the .java suffix when compiling the program. Remember, the command is javac HelloWorld.java not javac HelloWorld.
I have installed oracle jdk in /usr/lib/jvm/ and i have setted up path in etc/environment as
JAVA_HOME=/usr/lib/jvm/jdk1.7.0_51
PATH=$PATH:$JAVA_HOME/bin
But still when i am running javac, I am getting following error. The program 'javac' can be found in the following packages:
* default-jdk
* ecj
* gcj-4.6-jdk
* gcj-4.7-jdk
* openjdk-7-jdk
* openjdk-6-jdk
It means javac is not installed or java path has not setted properly, however i am able to see javac,java,jps and other programs in my /usr/lib/jvm/jdk1.7.0_51. I have searched enough about it but still not able to get solution of this problem.
The file /etc/environment is not a file executed by the shell (like a shell script); you cannot use $SOMETHING references in this file. Variables are not substituted in this file. So,
JAVA_HOME=/usr/lib/jvm/jdk1.7.0_51
PATH=$PATH:$JAVA_HOME/bin
the second line will not work like this. You have to put the exact path in.
JAVA_HOME=/usr/lib/jvm/jdk1.7.0_51
PATH=...:/usr/lib/jvm/jdk1.7.0_51/bin
The javac binary (and probably other java binaries) is/are not in your user's $PATH environment variable. There are several ways you can address this:
Add /usr/lib/jvm/jdk1.7.0_51/bin to your user's $PATH
environment variable. You can do this by adding a line similar to
the following in your user's .bash_profile:
export PATH=${PATH}:/usr/lib/jvm/jdk1.7.0_51/bin
You'll have to restart your terminal session for it to take effect.
Create symbolic links to the java binaries from some directory
that's already part of your path (such as /usr/bin)
sudo ln -s /usr/lib/jvm/jdk1.7.0_51/bin/java /usr/bin/
sudo ln-s /usr/lib/jvm/jdk1.7.0_51/bin/javac /usr/bin/
BTW: There are several other java executables in /usr/lib/jvm/jdk1.7.0_51/bin. see the symlink commands for java and javac above. You should run similar command for any other executables you may want to use.
Use the fully qualified path directly on the command line:
$ /usr/lib/jvm/jdk1.7.0_51/bin/javac
https://help.ubuntu.com/community/Java
have you tried this page? Its where I go when I need Java info. You may not have the one you installed set as default.
Could it be that you did not refresh the shell after change in path variable?
if you echo $PATH are the changes present?
I'm trying to use the command "ant build".The message says java home is not defined correctly we cannot execute /usr/bin/java//bin/java <notice the 2 slashes>
If i use the command echo $JAVA_HOME it returns usr/bin/java . What needs changing here?
The $JAVA_HOME variable does not refer to the java executable, but to the parent directory of the bin/java executable itself. This is the reason Ant complains of not being able to execute some cryptic /usr/bin/java//bin/java.
For example, in my case (Ubuntu 12.04, OpenJDK) the java home is set to
/usr/lib/jvm/java-6-openjdk-amd64/jre
where obviously there exists a /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java, of which /usr/bin/java ultimately represents a symbolic link.
Looks like Ant is assuming /usr/bin/java to start. Perhaps you don't need to set it.
Or try adding a leading slash (/usr instead of usr).
JAVA_HOME shouldn't be pointed to the java executable, rather it should be the parent directory of 'bin' where javac the compiler is located.
Usually the '/usr/bin/java' is a symbolic link to the actual executable in somewhere else, e.g., '/usr/lib/java/jdk*/bin/java', in which case the java home should be /usr/lib/java/jdk*.
I dad left Java since so long as a result now it happens that sometimes I forget the simple things and used to behave like a Stupid.
To run a Simple Java program say "Hello World" written in Notepad what do I have to Do?
I know the commands javac "Filename.java" and java "Filename" respectively to run it from the Command prompt.
But When I try to do that I got this message:
"javac is not recognized as an internal or external command, operable program or batch file."
and I could not Complie the file.
I hava little idea that we need to do some stuffs like setting the classpath or perhaps the path evnironment variables but it was exactly that I don't remember.
Can anybody please help me?
Thanks,
david
Add a JAVA_HOME env variable to point to the jdk installation directory
To your PATH env variable, add %JAVA_HOME%\bin
Add a CLASSPATH env variable to point to %JAVA_HOME%\lib.
remember to open a new console window and try running javac and java - everything should be fine now.
1) create JAVA_HOME environmental variable set value to java home directory
e.g. c:\program files\java\jdk1.5;
1) set PATH in environmental variable to your java bin directory
e.g. %JAVA_HOME%\bin
and to check classpath is set correctly run javac command on cmd
and this link will help to create and run simple java application
java tutorial
this might be usefull budddy
http://www.apl.jhu.edu/~hall/java/beginner/settingup.html
You need the JDK to be able to run javac.
I suggest you first start coding in eclipse, it provides all the environment set up for you. Once you get good with coding, you can try command prompt compiling and running. That way, you will be confident with language first and then go into the nitty-gritties of the environment and set up.
Its better to use any java IDE either eclipse or netBeans Download Link
But in case if you like to go through Command prompt method, then u need to set the paths. (These are the variables for your OS, that used to know where your commands e.g. java or javac etc are located). Hope from other answers you set the paths.
Good luck
I tried the following in cl:
javac Main.java
The shell gives an error that "javac" is not a recognized command. I know for a fact I have the Java Platform installed. What could be wrong?
(I use "cd" to set the directory first)
javac is most likely not on the PATH, and you must give the full path in your command.
Add /bin folder to your environment variables.
How do I set or change the PATH system variable?