java - IntelliJ GUI Designer Maven Executable JAR Export

Question

I'm using IntelliJ IDEA's GUI designer and Maven as build system. When I build the executable JAR file via this answer, the build succeeds. However, it throws an exception when launched via the command java -jar MyApplication.jar:

    Exception in thread "main" java.awt.IllegalComponentStateException: contentPane cannot be set to null.
            at javax.swing.JRootPane.setContentPane(JRootPane.java:621)
            at javax.swing.JFrame.setContentPane(JFrame.java:698)
...

The affected code line is the following:

setContentPane(panel);

When ran from source in IntelliJ, it works fine however Maven doesn't seem to properly build the JAR file. After all, IntelliJ does "magic" by linking to a .form file for keeping .java source code files clean from GUI code.

I also found a possible solution which involves adding a special plugin to the pom.xml file that seems to enable build support for IntelliJ's GUI designer here. So I ran mvn clean compile assembly:single again, it didn't have any errors however nothing changed.

If I do a mvn deploy, the plugin throws the following error:

[ERROR] Failed to execute goal org.codehaus.mojo:ideauidesigner-maven-plugin:1.0-beta-1:javac2 (default) on project MyApplication: Execution default of goal org.codehaus.mojo:ideauidesigner-maven-plugin:1.0-beta-1:javac2 failed: 16257 -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginExecutionException

Here is my pom.xml:

    <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>groupId</groupId>
    <artifactId>MyApplication</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <!-- Apache Commons Lang -->
        <dependency>
            <groupId>commons-lang</groupId>
            <artifactId>commons-lang</artifactId>
            <version>2.6</version>
        </dependency>

        <!-- Jsoup HTML parser -->
        <dependency>
            <groupId>org.jsoup</groupId>
            <artifactId>jsoup</artifactId>
            <version>1.8.3</version>
        </dependency>

        <!-- Apache Commons IO -->
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.4</version>
        </dependency>

        <!-- Apache Commons Validator -->
        <dependency>
            <groupId>commons-validator</groupId>
            <artifactId>commons-validator</artifactId>
            <version>1.4.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <archive>
                        <manifest>
                            <mainClass>com.example.MyApplication
                            </mainClass>
                        </manifest>
                        <manifestEntries>
                            <Built-By>BullyWiiPlaza</Built-By>
                        </manifestEntries>
                    </archive>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.3</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>

            <!-- IDEA Gui Designer Plugin -->
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>ideauidesigner-maven-plugin</artifactId>
                <version>1.0-beta-1</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>javac2</goal>
                        </goals>
                    </execution>
                </executions>

                <configuration>
                    <fork>true</fork>
                    <debug>true</debug>
                    <failOnError>true</failOnError>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

What is wrong? How do I properly export an executable JAR file using Maven in combination with IntelliJ's GUI designer?

Answer 1

That happens because Maven doesn't really know how to compile GUI created with IntelliJ GUI Designer. That's why you have to explicitly instruct IntelliJ to generate all the code it understands and Maven doesn't.

To do this go to GUI Designer settings and change the Generate GUI into value to Java Source files. From now on IntelliJ will include all the code responsible for setting UI up in the class itself and all the external tools, like Maven, Eclipse will work properly.