How to fix the error: test source folder 'src/test/java' in project must have an output folder that is not also used for main source"?

Question

I have installed mahout and I have imported the existing maven project apache-mahout-distribution-0.12.2 to Eclipse IDE for Java Developers and can not build and I couldn't fix these problems. Please share me your knowledge!

Simeon

This issue seems related: github.com/eclipse/eclipse.jdt.ls/issues/1635 – Dial

Answer 1

I had similar issue and had to type-in the name of the output folder directly in the .classpath as follows

<classpathentry kind="src" output="target/test-classes" path="src/test/java"/>

Note that 'contains test source' on Java Build Path panel should be set to 'Yes'. Once I did that and refreshed the output became visible in the Java Build Path panel.

Stomato

Answer 2

I had the same problem a couple of minutes ago. I tried some options as listed below and nothing happened:

• Changing the output folder specific for test class
• Changing the option 'Contains test sources' from no to yes and vice-versa
• Excluding all source folders on build path

My solution: I removed the project from my workspace and a new one was created.

Furthermore infomation about Test Source configuration at Eclipse, https://www.eclipse.org/eclipse/news/4.8/jdt.php#jdt-test-sources

Antecedent

What you mean by I removed from workspace and new one was created, who creates it? Mystical powers? – Strata

I removed and created manually a new one. – Antecedent

Answer 3

I had this problem and solved it as follows:

1. Right-click on project, Properties -> Java Build Path -> Source
2. Tick the "Allow output folders for source folders" checkbox
3. Now you can double-click on "Output folder" and set it per source folder path.

Frog

Answer 4

Surely it will be enough to open project's Java Build Path, focus the src/test/java folder and set its output folder as <project>/target/test-classes.

Hid

There is no separate output folder for test sources in my version. – Porscheporsena

@SridharSarnobat Strange that Jan Hrabowski's answer worked for you, and not mine, while both of them are doing the same in different ways. – Hid