Conflict with test classes with regular application

We use Gradle for the dependency management and for the deployment of the application. Our application is a regular Java application with a public main() method. Eclipse allows the starting of the application directly over a context menu (without Gradle).

However Eclipse adds the test classes to the class path. Since we use Spring configuration annotations for the test classes and for the actual applications we get conflicts. E.g. the database connection is instantiated twice Which leads to startup errors.

Is there a way to tell Eclipse to exclude the test classes to be added to the class path?

I know there is a gradle plugin 'applications', which allows the compilation and starting of the application. However we need to run multiple applications in parallel, which leads to lock issues with the gradle plugin.

Edit: I was unclear: The issue is that the project (libs.core) on which the actual project (applications.core) depends on has test classes which are included. The test classes of the actual project are not included in the Java class path.

For all projects we have the following structure:

Java Classes: src/main/java/
Test Classes: src/test/java

The .classpath file of the 'libs.core' project file contains the following:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="output" path=".eclipse-classes"/>
    <classpathentry kind="src" path="src/main/java"/>
    <classpathentry kind="src" path="src/main/resources"/>
    <classpathentry kind="src" path="src/test/java"/>
    <classpathentry kind="src" path="src/test/resources"/>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER" exported="true"/>
    <classpathentry sourcepath="[path to gradle cache]commons-logging-1.1.3-sources.jar" kind="lib" path="[path to gradle cache]commons-logging-1.1.3.jar" exported="true"/>
    [other dependencies]
</classpath>

The .classpath file of the 'applications.core' project file contains the following:

<?xml version="1.0" encoding="UTF-8"?>
<classpath>
    <classpathentry kind="output" path=".eclipse-classes"/>
    <classpathentry kind="src" path="src/main/java"/>
    <classpathentry kind="src" path="src/main/resources"/>
    <classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER" exported="true"/>
    <classpathentry kind="src" path="/libs.core" exported="true"/>
    <classpathentry sourcepath="[path to gradle cache]commons-logging-1.1.3-sources.jar" kind="lib" path="[path to gradle cache]commons-logging-1.1.3.jar" exported="true"/>
    [other dependencies]
</classpath>

Solution

The problem is, that eclipse doesn't understand the difference between test code and production code. As Makoto pointed out usually main code lays in src/main/java and test code in src/test/java. But even when following these conventions eclipse will pickup code from src/test/java when running your app. I see two options for you at the moment:

exclude the src/test folder manually in your run configuration
move your tests into a seperated test project

The clean solution would be that eclipse finally starts supporting different types of sources as idea does for years and java user all over the world are asking for for years.

cheers, René