diff --git a/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala b/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
index 4837b01d81..e09f1fc16f 100644
--- a/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
+++ b/core/src/main/scala/org/apache/spark/util/SizeEstimator.scala
@@ -131,8 +131,9 @@ object SizeEstimator extends Logging {
       return System.getProperty(TEST_USE_COMPRESSED_OOPS_KEY).toBoolean
     }
 
-    // java.vm.info provides compressed ref info for IBM JDKs
-    if (System.getProperty("java.vendor").contains("IBM")) {
+    // java.vm.info provides compressed ref info for IBM and OpenJ9 JDKs
+    val javaVendor = System.getProperty("java.vendor")
+    if (javaVendor.contains("IBM") || javaVendor.contains("OpenJ9")) {
       return System.getProperty("java.vm.info").contains("Compressed Ref")
     }
 
diff --git a/launcher/src/main/java/org/apache/spark/launcher/CommandBuilderUtils.java b/launcher/src/main/java/org/apache/spark/launcher/CommandBuilderUtils.java
index 47d2f8ef4e..172fb8c560 100644
--- a/launcher/src/main/java/org/apache/spark/launcher/CommandBuilderUtils.java
+++ b/launcher/src/main/java/org/apache/spark/launcher/CommandBuilderUtils.java
@@ -31,11 +31,6 @@ class CommandBuilderUtils {
   static final String DEFAULT_PROPERTIES_FILE = "spark-defaults.conf";
   static final String ENV_SPARK_HOME = "SPARK_HOME";
 
-  /** The set of known JVM vendors. */
-  enum JavaVendor {
-    Oracle, IBM, OpenJDK, Unknown
-  }
-
   /** Returns whether the given string is null or empty. */
   static boolean isEmpty(String s) {
     return s == null || s.isEmpty();
@@ -112,21 +107,6 @@ class CommandBuilderUtils {
     return os.startsWith("Windows");
   }
 
-  /** Returns an enum value indicating whose JVM is being used. */
-  static JavaVendor getJavaVendor() {
-    String vendorString = System.getProperty("java.vendor");
-    if (vendorString.contains("Oracle")) {
-      return JavaVendor.Oracle;
-    }
-    if (vendorString.contains("IBM")) {
-      return JavaVendor.IBM;
-    }
-    if (vendorString.contains("OpenJDK")) {
-      return JavaVendor.OpenJDK;
-    }
-    return JavaVendor.Unknown;
-  }
-
   /**
    * Updates the user environment, appending the given pathList to the existing value of the given
    * environment variable (or setting it if it hasn't yet been set).