UNIX for Dummies Questions & Answers

I need to run .java from a directory.

i.e. c:\aaa\bbb\ccc.java

first I compile all the java using javac *.java under the c:\aaa\bbb directory, now I want to run this command under cd .. ,

Here is the command that I need to type..

java -classpath /home/share/postgresql/java/postgresql.jar:. ccc

What do I need before ccc in order run ccc.java under the parent directory?

Just amend the classpath to add the path where java can find ccc.class

How do I do it? Could someone please tell me what to add into this command

java -classpath /home/share/postgresql/java/postgresql.jar:. ccc

You need to set you enviroment to reflect these:

setenv CLASSPATH /home/share/postgresql/java

or

set CLASSPATH=/home/share/postgresql/java; export CLASSPATH

Ensure that you JAVA_HOME is also define so you could execute any java programs from anywhere.

You may want to add them to your .bashrc or you .cshrc or what ever shell you are using.

type

java on the command line and see what options do you have.

for classpath you have to append the class name for java
to find ccc.class.

and for classpath each jar or class is seperated by ; in windows and : in unix.

Since You are on windows ... try this.

Code:

java -classpath /home/share/postgresql/java/postgresql.jar;PATHOFCCC/ccc.class  ccc

Or do the same thing in by setting CLASSPATH environment variable.

in windows

set CLASSPATH=%CLASSPATH%;PATHOFCCC\ccc.class

and run ccc.class as

java ccc





In unix ,
export CLASSPATH=$CLASSPATH:PATHOFCCC/ccc.class

and

java ccc

Usually I just set the classpath as an option to the java or javac command, instead of setting the CLASSPATH environment variable because it is likely that running/compiling one Java program needs a classpath different from another. Setting this environment variable overrides the default classpath up until the current session terminates. Sometimes you may not realize this environment variable is set, but somehow it has been defined somewhere, and you may get lots of classpath errors despite there should not be if it is not set (I have seen articles telling people to set the CLASSPATH in shell startup scripts, like .profile and the like).

A better way to manage all these is to write an Ant build file, similar to the concept of Makefiles, which has directives to override the list of classpaths. You can write a build file with two targets, one to compile it and another to run it. Then you can avoid a lot of troubles thereafter for writing really loooooong command-line arguments, as Ant knows how to compose the exact commands for you. It is particularly handy for projects that need to override the build paths.

More info? http://ant.apache.org