Develop Reference

Linux equivalent of including the classpath during compilation

I'm following a guide that only includes compilation instructions on windows. How would one run this build.bat file on Linux?
The batch file looks like this:
#echo off
#echo Compiling...
javac -classpath ..\..\lib\OneWireAPI.jar;%classpath% -d . .\src\*.java
And when I run the javac command on Linux, it fails:
javac -classpath ../../lib/OneWireAPI.jar;%classpath% -d . ./src/ReadTemp.java
The output is:
javac: no source files
What is the correct way to do this?

On Linux, you have to use : (colon) in place of ; (semicolon) as the path separator in Java options.
Also, if you have a classpath variable, in most common Linux shells it is referenced by $classpath rather than by %classpath%
javac -classpath ../../lib/OneWireAPI.jar:$classpath -d . ./src/ReadTemp.java

You have two items that did not get translated correctly from Windows CMD to Unix:
Path separator ; should be :.
Environment variables should be changed from %classpath% to $CLASSPATH format. Note that pretty much everything is case-sensitive in Linux, including environment variable names, and the Java path is traditionally all-caps.
Try
javac -classpath ../../lib/OneWireAPI.jar:$CLASSPATH -d . ./src/ReadTemp.java

Running Javac Command with classpath on linux

I have a folder Called TutorialFolder. Inside this, i have tutorial_class folder and WordCount.java file.
When I run wordcount program, it is giving below error.
hduser#ubuntu:~/Desktop/TutorialFolder$ javac -classpath ${HADOOP_CLASSPATH}-d '/home/hduser/Desktop/TutorialFolder/tutorial_class' '/home/hduser/Desktop/TutorialFolder/WordCount.java'
javac: invalid flag: /home/hduser/Desktop/TutorialFolder/tutorial_class
Usage: javac <options> <source files>
use -help for a list of possible options

The problem here is with the variable ${HADOOP_CLASSPATH} which is not set or empty. Thus the command is interpreted as,
javac -classpath -d /home/hduser/Desktop/TutorialFolder/tutorial_class /home/hduser/Desktop/TutorialFolder/WordCount.java
Fix the $HADOOP_CLASSPATH variable, the command should work.
Or, Try with hadoop classpath command
javac -classpath `hadoop classpath` -d /home/hduser/Desktop/TutorialFolder/tutorial_class /home/hduser/Desktop/TutorialFolder/WordCount.java

Javac classpath (.java file)

I want to compile a java file from the command line using this command: javac -cp C:/Java myPgm.java but it keeps saying that
javac: file not found: myPgm.java
Usage: javac <options> <source files>
use -help for a list of possible options
any help please? ;)

run the following code in the terminal to compile the java source code
javac C:/Java/myPgm.java
then to execute the code
java theClassNameOfTheJavaFile

go to your current directory then
type
javac myPgm.java
then
java myPgm
if program inside package then
javac -d . myPgm.java
and then
java package_name.myPgm

javac: not a directory: src\com\example\web\BeerSelect.java

I am on chapter 3 of Headfirst Servlets and JSP.
This is my input to windows 7 command line:
D:\Workspaces\ServletsJSP\MyProjects\beerV1>javac -classpath
C:\Tomcat\tomcat\lib\servlet-api.jar;classes;. -d
src\com\example\web\BeerSelect.java
This is the error message:
javac: not a directory: src\com\example\web\BeerSelect.java
Usage: javac <options> <source files>
use -help for a list of possible options
I have BeerSelect.java in this directory: D:\Workspaces\ServletsJSP\MyProjects\beerV1\src\com\example\web

The -d flag is used to specify which directory to output to. You seem to have omitted it's argument, so it thinks you want to output into a directory called src\com\example\web\BeerSelect.java, which of course is not a directory.

You haven't specified the directory of the -d flag. This flag is used to specify where the class file should be put. You probably want to change your command to something like this:
D:\Workspaces\ServletsJSP\MyProjects\beerV1>javac -classpath C:\Tomcat\tomcat\lib\servlet-api.jar;classes;. -d bin src\com\example\web\BeerSelect.java
Assuming bin is where you want your class files.

javac no source files found

I have the .java file on the current working directory but javac reports:
javac: no source files
Usage: javac <options> <source files>
use -help for a list of possible options
I'm working on ubuntu.

From your comment above, it looks like you tried:
javac -cp .;lib.jar a.java on your Ubuntu system. The CLASSPATH separator is : on Unix systems and ; on Windows.
Ubuntu considered the command up to the ;, java -cp . and thus gave the message.
javac -cp .:lib.jar a.java should compile fine.

For anyone who is using powersehll on windows use CLASSPATH separator : instead of ;

I tried a similar thing and found that you need to mention the absolute path when you are using the
-cp and -d option with javac like this
javac -cp 'ur location of jars & files'; -d 'location to add your classes to' 'absolute path of file'
eg:
javac -cp C:\home\lib\mywork; -d c:\home\classes c:\home\files*.java

for javac, there are options and arguments
arg: it takes argument as path of source file
options: we require for basic compilation
-sourcepath: the path of dependent source files
-d: directory path of output classes
javac -sourcepath './src' -d './bin' -verbose './src/App.java'