No need to print the default classpath. In Java, the default classpath is just the current directory:

If -classpath and -cp are not used and CLASSPATH is not set, the user class path consists of the current directory (.).

(documentation of java:)

Note: For completeness' sake: Theree are two other paths where java will look for stuff:

• the bootstrap class path
• the extension directory

The bootstrap class path by default points to parts of the JDK, and you almost never want to mess with it (unless you want to override part of the JDK), so you probably should not worry about it. The extension directories are for extending the JDK; see http://docs.oracle.com/javase/7/docs/technotes/guides/extensions/index.html

It appears that IntelliJ 11 has changed the method, and the checked answer no longer works for me. In case anyone else arrives here via a search engine, here's how I solved it in IntelliJ 11:

1. Go to the Project Structure, click on Modules, and click on your Module
2. Choose the "Dependencies" tab
3. Click the "+" button on the right-hand side and select "Jars or directories..."
4. Add the directory(ies) you want (note you can multi-select) and click OK
5. In the dialog that comes up, select "classes" and NOT "jar directory"
6. Make sure you're using that Module in your run target

Note that step 5 seems to be the key difference. If you select "jar directory" it will look exactly the same in the IDE but won't include the path at runtime. There appears to be no way to determine whether you've previously selected "classes" or "jar directory" after the fact.