docs/attachments/LUCENE-6538/LUCENE-6538.patch

Index: lucene/core/src/java/org/apache/lucene/index/IndexWriter.java
===================================================================
--- lucene/core/src/java/org/apache/lucene/index/IndexWriter.java	(revision 1684477)
+++ lucene/core/src/java/org/apache/lucene/index/IndexWriter.java	(working copy)
@@ -3769,6 +3769,15 @@
     setDiagnostics(info, source, null);
   }
 
+  private static void addSysPropIfNotNull(Map<String,String> diagnostics, String key) {
+    String s = System.getProperty(key);
+    if (s != null) {
+      diagnostics.put(key, s);
+    } else {
+      diagnostics.put(key, "undefined");
+    }
+  }
+
   private static void setDiagnostics(SegmentInfo info, String source, Map<String,String> details) {
     Map<String,String> diagnostics = new HashMap<>();
     diagnostics.put("source", source);
@@ -3778,6 +3787,10 @@
     diagnostics.put("os.version", Constants.OS_VERSION);
     diagnostics.put("java.version", Constants.JAVA_VERSION);
     diagnostics.put("java.vendor", Constants.JAVA_VENDOR);
+    // On IBM J9 JVM this is better than java.version which is just 1.7.0 (no update level):
+    addSysPropIfNotNull(diagnostics, "java.runtime.version");
+    // Hotspot version, e.g. 2.8 for J9:
+    addSysPropIfNotNull(diagnostics, "java.vm.version");
     diagnostics.put("timestamp", Long.toString(new Date().getTime()));
     if (details != null) {
       diagnostics.putAll(details);
Index: lucene/core/src/test/org/apache/lucene/index/TestCheckIndex.java
===================================================================
--- lucene/core/src/test/org/apache/lucene/index/TestCheckIndex.java	(revision 1684477)
+++ lucene/core/src/test/org/apache/lucene/index/TestCheckIndex.java	(working copy)
@@ -93,6 +93,9 @@
     assertEquals(18, seg.termVectorStatus.docCount);
     assertEquals(18, seg.termVectorStatus.totVectors);
 
+    assertNotNull(seg.diagnostics.get("java.vm.version"));
+    assertNotNull(seg.diagnostics.get("java.runtime.version"));
+
     assertTrue(seg.diagnostics.size() > 0);
     final List<String> onlySegments = new ArrayList<>();
     onlySegments.add("_0");