IntelliJ IDEA 13 debugger don't stop on breakpoint in java for maven project

Question 1

Update 2021:

Nowadays, on most situations, debugging should work out of the box.

Newer versions of IntelliJ IDEA (tested with 2020.3) can now auto-detect maven exec configurations and add the proper options to enable debugging. See IDEA-189973 for further info. Thanks @Gili for opening a ticket for this functionality back in 2018.

Nevertheless my original answer bellow can still be useful for older versions of IntelliJ, Remote Debugging or to debug while using certain Maven / Gradle plugins that Fork the VM and require debugging options to be manually passed downstream (adjust configuration accordingly).

My solution:

Considering that you have a program that depends on system properties:

package com.mycompany.app;


public class App {

    private static final String GREETING = System.getProperty("greeting", "Hi");

    public static void main(String[] args) {
        int x = 10;
        System.out.println(GREETING);
    }
}

And you are running it with exec:exec:

mvn exec:exec -Dexec.executable=java "-Dexec.args=-classpath %classpath -Dgreeting=\"Hello\" com.mycompany.app.App"

With some "inception magic" we can debug the process started by Mavenexec:exec.

Maven

Change your exec:exec goal to enable remote debugging. I'm using suspend=y and server=n, but feel free to configure the JDWP Agent as you please:

-agentlib:jdwp=transport=dt_socket,server=n,address=127.0.0.1:8000,suspend=y`

This will not be passed directly to the maven JVM, instead it will be passed to exec.args which will be used by exec:exec:

mvn exec:exec -Dexec.executable=java "-Dexec.args=-classpath %classpath -agentlib:jdwp=transport=dt_socket,server=n,address=127.0.0.1:8000,suspend=y -Dgreeting=\"Hello\" com.mycompany.app.App"

IntelliJ IDEA

Create a Remote configuration (again I'm using a Listen strategy. You should adjust it accordingly):

Now toggle your breakpoints and Debug your remote configuration. Using the settings above it will wait until your process starts:

Finally run the exec:exec line above and debug your application at will:

So basically you need two "Run/Debug" configurations for this to work:

A Maven configuration for exec:exec with the system properties and JDWP agent configuration:

The remote configuration acting as a client.

Question 2

The exec goal will execute your program in a separate process, so the debugger may not be connecting to the right JVM. Instead try using the java goal, e.g.:

mvnDebug install exec:java

This will execute your program in the same process and hopefully you will hit your breakpoint.

Question 3

To debug web applications in maven projects using the Intellij Community Edition, you can add a tomcat or jetty plugin to your WAR pom like this:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.tomcat.maven</groupId>
            <artifactId>tomcat7-maven-plugin</artifactId>
            <configuration>
                <port>8080</port>
                <path>/yourapp</path>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.mortbay.jetty</groupId>
            <artifactId>maven-jetty-plugin</artifactId>
        </plugin>
    </plugins>
</build>

It's possible if needed to add database drivers like this:

<plugin>
    <groupId>org.mortbay.jetty</groupId>
    <artifactId>maven-jetty-plugin</artifactId>
    <dependencies>
        <dependency>
           ... your database driver groupId and artifactId ...
        </dependency>
    </dependencies>
</plugin>

Then using these plugins the application can be started in the command line (from the pom directory):

mvnDebug clean install tomcat7:run-war

Or for jetty:

mvnDebug clean install jetty:run-war

With the application running in debug mode from the command line (you don't need to run it from Intellij), do a remote debugging configuration similar to what you posted and the breakpoint should be hit.

If you use Intellij Ultimate Edition then this is not necessary, because you can create a server configuration for Tomcat or any other server and deploy the application in a fully integrated way, with debugging and hot deployment handled transparently.

There is a 30 day trial where you can evaluate this feature and others.