Question

Working with some basic java apps on CentOS 5 linux and I have my classpath set to point to home/pathToJava/bin which contains javac and java

and I have .java files in home/pathToFolderA/src

and home/pathToFolderB/gen-java

When I run javac and java in home/pathToFolderA/src everything works perfectly

But when I run javac from within home/pathToFolderB/gen-java on fileName.java I get a file not found error, specifically

javac: file Not found: fileName.java
Usage: javac <options> <source files>

Why could this be happening?

Thanks for all help

Answer 1

You shouldn’t set your classpath to point to your JDK bin directory — instead it should be the PATH environment variable, which serves a different purpose to classpath. (The classpath defines a list of jars and directories containing compiled Java .class code; the PATH variable defines a list of paths where the shell needs to look and locate programs to execute when they are not found in the current directory — so if you type for instance zip — it would look in all the directories defined in PATH and figure out that zip program is located under /usr/bin)
Secondly if you want to compile sources from both directory you need to specify:

• all the paths where the sources are (both home/pathToFolderA/src and home/pathToFolderB/gen-java)
• the path where the compiled .class files to be generated
• specify in the classpath any library you might use in your source files

To sum it up, it would be something like this to compile:

javac -d /home/pathToFolderWithResultsOfCompilation -classpath /path/to/some.jar:/path/to/another.jar home/pathToFolderA/src/*.java home/pathToFolderB/gen-java/*.java 

and to run your compiled programs:

java -classpath /path/to/some.jar:/path/to/another.jar:/home/pathToFolderWithResultsOfCompilation full.name.of.your.Java