Including all the jars in a directory within the Java classpath

Question

Is there a way to include all the jar files within a directory in the classpath?

I\'m trying java -classpath lib/*.jar:. my.package.Program and it is no

Answer 1

Short answer: java -classpath lib/*:. my.package.Program

Oracle provides documentation on using wildcards in classpaths here for Java 6 and here for Java 7, under the section heading Understanding class path wildcards. (As I write this, the two pages contain the same information.) Here's a summary of the highlights:

• In general, to include all of the JARs in a given directory, you can use the wildcard * (not *.jar).

• The wildcard only matches JARs, not class files; to get all classes in a directory, just end the classpath entry at the directory name.

• The above two options can be combined to include all JAR and class files in a directory, and the usual classpath precedence rules apply. E.g. -cp /classes;/jars/*

• The wildcard will not search for JARs in subdirectories.

• The above bullet points are true if you use the CLASSPATH system property or the -cp or -classpath command line flags. However, if you use the Class-Path JAR manifest header (as you might do with an ant build file), wildcards will not be honored.

Yes, my first link is the same one provided in the top-scoring answer (which I have no hope of overtaking), but that answer doesn't provide much explanation beyond the link. Since that sort of behavior is discouraged on Stack Overflow these days, I thought I'd expand on it.

Answer 2

class from wepapp:

  > mvn clean install

  > java -cp "webapp/target/webapp-1.17.0-SNAPSHOT/WEB-INF/lib/tool-jar-1.17.0-SNAPSHOT.jar;webapp/target/webapp-1.17.0-SNAPSHOT/WEB-INF/lib/*" com.xx.xx.util.EncryptorUtils param1 param2

Answer 3

For me this works in windows .

java -cp "/lib/*;" sample

For linux

java -cp "/lib/*:" sample

I am using Java 6

Answer 4

For windows quotes are required and ; should be used as separator. e.g.:

java -cp "target\\*;target\\dependency\\*" my.package.Main

Answer 5

All the above solutions work great if you develop and run the Java application outside any IDE like Eclipse or Netbeans.

If you are on Windows 7 and used Eclipse IDE for Development in Java, you might run into issues if using Command Prompt to run the class files built inside Eclipse.

E.g. Your source code in Eclipse is having the following package hierarchy: edu.sjsu.myapp.Main.java

You have json.jar as an external dependency for the Main.java

When you try running Main.java from within Eclipse, it will run without any issues.

But when you try running this using Command Prompt after compiling Main.java in Eclipse, it will shoot some weird errors saying "ClassNotDef Error blah blah".

I assume you are in the working directory of your source code !!

Use the following syntax to run it from command prompt:

1. javac -cp ".;json.jar" Main.java

2. java -cp ".;json.jar" edu.sjsu.myapp.Main

   [Don't miss the . above]

This is because you have placed the Main.java inside the package edu.sjsu.myapp and java.exe will look for the exact pattern.

Hope it helps !!

Answer 6

Not a direct solution to being able to set /* to -cp but I hope you could use the following script to ease the situation a bit for dynamic class-paths and lib directories.

 libDir2Scan4jars="../test";cp=""; for j in `ls ${libDir2Scan4jars}/*.jar`; do if [ "$j" != "" ]; then cp=$cp:$j; fi; done; echo $cp| cut -c2-${#cp} > .tmpCP.tmp; export tmpCLASSPATH=`cat .tmpCP.tmp`; if [ "$tmpCLASSPATH" != "" ]; then echo .; echo "classpath set, you can now use  ~>         java -cp \$tmpCLASSPATH"; echo .; else echo .; echo "Error please check libDir2Scan4jars path"; echo .; fi; 

Scripted for Linux, could have a similar one for windows too. If proper directory is provided as input to the "libDir2Scan4jars"; the script will scan all the jars and create a classpath string and export it to a env variable "tmpCLASSPATH".