Patch for the retired Maven IDEA plugin (version 2.2.1) to allow setting the language level in the IDEA configuration file.

set-language-level.patch

Index: src/main/java/org/apache/maven/plugin/idea/IdeaProjectMojo.java
===================================================================
--- src/main/java/org/apache/maven/plugin/idea/IdeaProjectMojo.java	(revision 1658114)
+++ src/main/java/org/apache/maven/plugin/idea/IdeaProjectMojo.java	(working copy)
@@ -161,6 +161,11 @@
                 setJdkName( module, defaultJdkName );
             }
 
+            if ( jdkLevel != null )
+            {
+                setJdkLevel(module, jdkLevel);
+            }
+
             setWildcardResourcePatterns( module, wildcardResourcePatterns );
 
             Element component = findComponent( module, "ProjectModuleManager" );
@@ -258,6 +263,12 @@
         }
     }
 
+    private void setJdkLevel( Element content, String jdkLevel )
+    {
+        Element component = findComponent( content, "ProjectRootManager" );
+        component.addAttribute( "languageLevel", "JDK_" + jdkLevel.replace( '.', '_' ) );
+    }
+
     /**
      * Sets the wilcard resource patterns.
      *
Index: src/test/java/org/apache/maven/plugin/idea/IdeaProjectTest.java
===================================================================
--- src/test/java/org/apache/maven/plugin/idea/IdeaProjectTest.java	(revision 1658114)
+++ src/test/java/org/apache/maven/plugin/idea/IdeaProjectTest.java	(working copy)
@@ -75,6 +75,7 @@
         Document iprDocument = executeMojo( "src/test/project-plugin-configs/plugin-config-jdk15.xml" );
 
         testJdkName( iprDocument, "1.5", "java version 1.5" );
+        testJdkLevel( iprDocument, "JDK_1_5" );
     }
 
     public void testIdeaProjectWithModules()
@@ -153,6 +154,19 @@
         }
     }
 
+    private void testJdkLevel( Document document, String expectedJdkLevel )
+        throws Exception
+    {
+        Element root = document.getRootElement();
+
+        Element component = findComponent( root, "ProjectRootManager" );
+
+        String jdkLevel = component.attributeValue( "languageLevel" );
+
+        assertEquals("lagnuageLevel must be set correctly",
+                expectedJdkLevel, jdkLevel);
+    }
+
     protected Document executeMojo( String pluginXml )
         throws Exception
     {