I am facing a very strange type of java classpath problem. I have added path d:\javaext in the java classpath environment variable and when enter on the command prompt echo %classpath% , it shows the said path in the printed list but even then, when I try to compile a java file in which I am importing the package by adding import org.apache.commons.lang.*;, it some how says that the said package doesn't exist. The relevant jar file physically exists on that path also. Any clue that what am I missing, although it's a very basic stuff. I have also tried compiling it with setting the classpath on runtime by javac -cp or javac -classpath switch but even then no success.
I am trying to compile the code with java 1.8 on windows 8.1
Can Anybody tell that what this alert means in the property dialog box of the jar file?
Your .Jar file might be corrupt.
Else on Windows try to set path through Environment Variable.
And on Linux , export the path for temporary usage or set in bashrc or bash profile.....
This could be caused by differences between version of a certain "jar", some third-party libraries does not support backward compatibility. So, try browsing through the "jar" to find the package-class combination that you are using.
Hope this helps,
Brian
Is it safe to assume that the are no spaces inside the path, e.g. "C:\Program Files"? If there are spaces, try surrounding the classpath variable with quotes.
Related
I'm getting the following error when I try to run the 'jar' command in the command line on windows :
'jar' is not recognized as an internal or external command
The general solution seems to be that I need to add the jdk bin folder to the PATH in environment variables. I have already done this, I added the following to the path variable :
...; C:\Program Files\Java\jdk1.8.0_40\bin\;
Though I'm not sure if having the jdk reside in 'program files' instead of 'program files x86' affects this. I'm on 64 bit windows with 64 bit java.
Thanks
The path should only contain directories where the OS will look for executables. Strip the trailing "\jar.exe" to set your path as:
(old path variables here);C:\Program Files (x86)\Java\jdk1.7\bin
Thanks To : #stevevls
Try using this command:
java -version
If it doesn't work that means you failed to properly add path to jdk.
If it does work, try using:
java -jar
The jar command in command line is used in order to create a JAR file. For example:
jar cf jar-file input-file(s)
See more at: Oracle docs
If you want to run the existed JAR file you should use the java -jar command mentioned by #Aleksandr.
But in your case it looks like you don't have an access to the added directory in your path with JKD binaries so at the beginning try to execute mentioned java --version to check whether you have java in you classpath at all.
Please remember that on Windows you have to restart the console when you change the windows default path. You do not see the changes on the current console.
The x64 version of Java is installed on Program Files. The x86 version is installed on Program Files x86 by default.
Five steps to solve this problem:
check whether in your bin folder jar.exe is availbale or not
check for your environmental setting
download jar file from here http://originaldll.com/file/jar.exe/29248.html and keep in bin folder
now check for jar it will 100% work
keep any jar in your desktop and go to desktop path on cmd prompt and run the command jar xf filename.jar
Now see if it is working
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.
My environment is Windows 7 and JDK 1.7.
I have not set the CLASSPATH environment variable; echo %CLASSPATH% outputs nothing.
Java compiler: C:\Program Files\Java\jdk1.7.0_10\bin
Java source: is in D:\tmpmulu\Tj.java
I run the command like below:
C:\>"C:\Program Files\Java\jdk1.7.0_10\bin\javac.exe" -cp d:\tmpmulu\ d:\tmpmulu\Tj.java
It works. The command set the classpath and compiled the file.
But when I change the command to use . instead of d:\tmpmulu\ as my classpath:
C:\>"C:\Program Files\Java\jdk1.7.0_10\bin\javac.exe" -cp . d:\tmpmulu\Tj.java
It's also OK.
That confused me. The . means the current path, it should be c:\. How did it run successfully?
Another question is command like below:
C:\>"C:\Program Files\Java\jdk1.7.0_10\bin\javac.exe" -cp d:\tmpmulu\ Tj.java
As my thinking, the classpath is set to d:\tmpmulu\, it should find the Tj.java file. But the result is 'file not found Tj.java'.
Can anyone tell me details?
Well, presumably your code doesn't rely on having anything in the classpath, basically. If it only uses classes from the JDK, that's absolutely fine.
Note that the classpath is only used to find class files - not source code. That explains both the lack of failure when your source path isn't on the classpath, and then failure when you try to use the classpath to locate Tj.java.
First, if you're compiling with javac -cp . myClass.java, you can omit it the -cp . completely, since it's the default classpath.
Second, -cp should be used when you need to specify references to additional JARs file not included in the standard JDK library, such as a jdbc connector. If your class doesn't require any additional library, then it doesn't really matter what directory you tell javac to look into.
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!