diff --git a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
index e96d1764..776cd4ed 100644
--- a/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
+++ b/modules/kobalt-plugin-api/src/main/kotlin/com/beust/kobalt/internal/JvmCompilerPlugin.kt
@@ -272,7 +272,7 @@ abstract class JvmCompilerPlugin @Inject constructor(
         val extraSourceFiles = arrayListOf<String>()
         if (sourceSuffixes.any { it.contains("kt")}) {
             project.sourceDirectories.forEach {
-                if (it.contains("java")) extraSourceFiles.add(it)
+                if (it.contains("java")) extraSourceFiles.add(KFiles.joinDir(project.directory, it))
             }
         }