CODEWITHSUNDEEP
javaclasspath
user739991
user739991

Reputation: 21

how to set argument for classpath

to launch tests , I have to set a big list of jar files as arguments for classpath : -classpath a.var;b.jar;.... - Is there an other way to specify libraries ? for example is it possible to set file as arguments and the file contains path to all libraries example : -classpath myFile.txt and myFile.txt contains ../a.jar ../b.jar .. etc

thanks,

Upvotes: 2

Views: 18272

Answers (5)

Peter Knego
Peter Knego

Reputation: 80340

You can programmatically add a new path to classpath:

String currentPath = System.getProperty("java.library.path");
System.setProperty( "java.library.path", current + ":/path/to/my/libs" );

// this forces JVM to reload "java.library.path" property
Field fieldSysPath = ClassLoader.class.getDeclaredField( "sys_paths" );
fieldSysPath.setAccessible( true );
fieldSysPath.set( null, null );

You can add a path, so no need to list all jars. This changes classpath only for your JVM instance, so it will not affect other java applications.

Update:

: and / are UNIX-specific lib-path and folder-path separators. For multi-OS you should use "path.separator" and "file.separator" system properties.

Upvotes: 3

Michael Borgwardt
Michael Borgwardt

Reputation: 346327

Since Java 6, you can use wildcards in your classpath:

java -classpath 'lib/*'

Note that you must quote the classpath string to avoid having the shell expand the wildcard.

Upvotes: 3

JB Nizet
JB Nizet

Reputation: 691805

Since Java 6, you may use wildcards in classpath, to include all jars in a directory. See http://download.oracle.com/javase/6/docs/technotes/tools/windows/classpath.html.

Upvotes: 2

justkt
justkt

Reputation: 14766

You can set the environment variable CLASSPATH (use the proper syntax for your shell to do this, ex. bash, Windows XP, etc).

You can also create some sort of profile file that does this for you all the time, ex .bashrc. This will affect every time the java command is used under that profile, of course.

If your main class is in a jar, you can also use the jar's manifest to set the classpath. Sun/Oracle has a tutorial page on doing this. Create a file called Manifest.txt. In that file add the line:

Class-Path: jar1-name jar2-name directory-name/jar3-name

where the various jar1-name parts are actual jars on your classpath.

Then create your jar using:

jar cfm MyJar.jar Manifest.txt MyPackage/*.class

Or the Ant Jar Task with manifest attribute set, or use the Maven jar plugin or however your build works, get the manifest set for the jar.

Or continue to use --classpath as you are currently.

Upvotes: 2

Vladimir Dyuzhev
Vladimir Dyuzhev

Reputation: 18336

To lunch tests I strongly suggest you to use Ant.

And Ant has <classpath> element, which allows you to specify "all jars within given directory":

<classpath>
  <pathelement path="${classpath}"/>
  <fileset dir="lib">
    <include name="**/*.jar"/>
  </fileset>
  <pathelement location="classes"/>
  <dirset dir="${build.dir}">
    <include name="apps/**/classes"/>
    <exclude name="apps/**/*Test*"/>
  </dirset>
  <filelist refid="third-party_jars"/>
</classpath>

Upvotes: 1

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