diff --git a/src/main/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParser.java b/src/main/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParser.java
index df91864..8f10cb3 100644
--- a/src/main/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParser.java
+++ b/src/main/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParser.java
@@ -2,10 +2,10 @@
 
 import hudson.model.ParametersDefinitionProperty;
 
-import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import org.apache.commons.lang.StringUtils;
 import org.jenkinsci.plugins.parameterizedscheduler.Messages;
@@ -47,9 +47,9 @@ public String checkSanity(String cronTabSpec, ParametersDefinitionProperty param
 			if (split.length == 2) {
 				try {
 					Map<String, String> parsedParameters = parse(split[1]);
-					List<String> parameterDefinitionNames = parametersDefinitionProperty.getParameterDefinitionNames();
-					List<String> parsedKeySet = new ArrayList<>(parsedParameters.keySet());
-					parsedKeySet.removeAll(parameterDefinitionNames);
+					List<String> parameterDefinitionNames = parametersDefinitionProperty != null
+							? parametersDefinitionProperty.getParameterDefinitionNames() : Collections.emptyList();
+					List<String> parsedKeySet = parsedParameters.keySet().stream().filter(s -> !parameterDefinitionNames.contains(s)).collect(Collectors.toList());
 					if (!parsedKeySet.isEmpty()) {
 						return Messages.ParameterizedTimerTrigger_UndefinedParameter(parsedKeySet, parameterDefinitionNames);
 					}
diff --git a/src/test/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParserTest.java b/src/test/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParserTest.java
index 92ca437..44b5caa 100644
--- a/src/test/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParserTest.java
+++ b/src/test/java/org/jenkinsci/plugins/parameterizedscheduler/ParameterParserTest.java
@@ -1,10 +1,12 @@
 package org.jenkinsci.plugins.parameterizedscheduler;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import hudson.model.ParametersDefinitionProperty;
 
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 
@@ -153,8 +155,14 @@ public void checkSanity_duplicateParamName() throws Exception {
 	@Test
 	public void checkSanity_UnmatchedEquals() throws Exception {
 		ParameterParser testObject = new ParameterParser();
-
 		testObject.checkSanity("* * * * *%name=value;name2=", mockParametersDefinitionProperty);
 	}
 
+	@Test
+	public void checkSanity_NullParameters() throws Exception {
+		ParameterParser testObject = new ParameterParser();
+		assertEquals(Messages.ParameterizedTimerTrigger_UndefinedParameter(Collections.singletonList("name"), Collections.emptyList()),
+				testObject.checkSanity("* * * * *%name=value", null));
+	}
+
 }