diff --git a/libs/grok/src/main/resources/patterns/java b/libs/grok/src/main/resources/patterns/java
index e968006ad2d20..01766b8ebd165 100644
--- a/libs/grok/src/main/resources/patterns/java
+++ b/libs/grok/src/main/resources/patterns/java
@@ -7,8 +7,6 @@ JAVAMETHOD (?:(<init>)|[a-zA-Z$_][a-zA-Z$_0-9]*)
 JAVASTACKTRACEPART %{SPACE}at %{JAVACLASS:class}\.%{JAVAMETHOD:method}\(%{JAVAFILE:file}(?::%{NUMBER:line})?\)
 # Java Logs
 JAVATHREAD (?:[A-Z]{2}-Processor[\d]+)
-JAVACLASS (?:[a-zA-Z0-9-]+\.)+[A-Za-z0-9$]+
-JAVAFILE (?:[A-Za-z0-9_.-]+)
 JAVASTACKTRACEPART at %{JAVACLASS:class}\.%{WORD:method}\(%{JAVAFILE:file}:%{NUMBER:line}\)
 JAVALOGMESSAGE (.*)
 # MMM dd, yyyy HH:mm:ss eg: Jan 9, 2014 7:13:13 AM
diff --git a/libs/grok/src/test/java/org/elasticsearch/grok/GrokTests.java b/libs/grok/src/test/java/org/elasticsearch/grok/GrokTests.java
index 7c1b473c6b3a1..b1cc608a5ca2d 100644
--- a/libs/grok/src/test/java/org/elasticsearch/grok/GrokTests.java
+++ b/libs/grok/src/test/java/org/elasticsearch/grok/GrokTests.java
@@ -446,6 +446,16 @@ public void testUnsupportedBracketsInFieldName() {
         assertNull(matches);
     }
 
+    public void testJavaClassPatternWithUnderscore() {
+        Grok grok = new Grok(basePatterns, "%{JAVACLASS}");
+        assertThat(grok.match("Test_Class.class"), is(true));
+    }
+
+    public void testJavaFilePatternWithSpaces() {
+        Grok grok = new Grok(basePatterns, "%{JAVAFILE}");
+        assertThat(grok.match("Test Class.java"), is(true));
+    }
+
     private void assertGrokedField(String fieldName) {
         String line = "foo";
         Grok grok = new Grok(basePatterns, "%{WORD:" + fieldName + "}");