diff --git a/java/compiler/impl/src/com/intellij/compiler/server/impl/BuildProcessClasspathManager.kt b/java/compiler/impl/src/com/intellij/compiler/server/impl/BuildProcessClasspathManager.kt
index 53d42869c32a..89d8fb0e2f4a 100644
--- a/java/compiler/impl/src/com/intellij/compiler/server/impl/BuildProcessClasspathManager.kt
+++ b/java/compiler/impl/src/com/intellij/compiler/server/impl/BuildProcessClasspathManager.kt
@@ -1,4 +1,4 @@
-// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.compiler.server.impl
 
 import com.google.common.collect.HashBiMap
@@ -157,7 +157,7 @@ private fun findClassesRoot(relativePath: String, plugin: IdeaPluginDescriptor,
   if (PluginManagerCore.isRunningFromSources()) {
     val fileName = FileUtilRt.getNameWithoutExtension(PathUtilRt.getFileName(relativePath))
     //try restoring module name from JAR name automatically generated by BaseLayout.convertModuleNameToFileName
-    val moduleName = "intellij." + fileName.replace('-', '.')
+    val moduleName = if (relativePath.startsWith("modules/")) fileName else "intellij." + fileName.replace('-', '.')
     val mapping = PathManager.getArchivedCompiledClassesMapping()
     if (mapping != null) {
       // baseFile is ".../idea-compile-parts-v2/production/<module-name>/"
diff --git a/plugins/IntelliLang/java-support/resources/intellij.java.langInjection.xml b/plugins/IntelliLang/java-support/resources/intellij.java.langInjection.xml
index b0fbba1e4049..762dab4c0f3a 100644
--- a/plugins/IntelliLang/java-support/resources/intellij.java.langInjection.xml
+++ b/plugins/IntelliLang/java-support/resources/intellij.java.langInjection.xml
@@ -32,7 +32,7 @@
 
   <extensions defaultExtensionNs="com.intellij">
     <tipAndTrick file="InjectSQLLanguage.html"/>
-    <compileServer.plugin classpath="java-langInjection-jps.jar"/>
+    <compileServer.plugin classpath="java-langInjection-jps.jar;modules/intellij.java.langInjection.jps.jar"/>
     <languageInjectionPerformer language="JAVA"
                                 implementationClass="org.intellij.plugins.intelliLang.inject.java.JavaInjectionPerformer"/>
   </extensions>