diff --git a/src/main/kotlin/com/cognifide/gradle/common/CommonPlugin.kt b/src/main/kotlin/com/cognifide/gradle/common/CommonPlugin.kt
index 752c6fb..14eadfa 100644
--- a/src/main/kotlin/com/cognifide/gradle/common/CommonPlugin.kt
+++ b/src/main/kotlin/com/cognifide/gradle/common/CommonPlugin.kt
@@ -44,7 +44,7 @@ class CommonPlugin : Plugin<Project> {
      */
     private fun checkPathEnabled(project: Project): Boolean {
         val envVars = listOf("JENKINS_HOME")
-        if (envVars.any { System.getenv(it).isNotBlank() }) {
+        if (envVars.any { (System.getenv(it) ?: "").isNotBlank() }) {
             return false
         }
 
diff --git a/src/main/kotlin/com/cognifide/gradle/common/build/PropertyParser.kt b/src/main/kotlin/com/cognifide/gradle/common/build/PropertyParser.kt
index 5c453af..97e89e2 100644
--- a/src/main/kotlin/com/cognifide/gradle/common/build/PropertyParser.kt
+++ b/src/main/kotlin/com/cognifide/gradle/common/build/PropertyParser.kt
@@ -18,12 +18,12 @@ class PropertyParser(anyProject: Project) {
             return project.property(name).toString()
         }
 
-        val systemValue = System.getProperty(name)
+        val systemValue: String? = System.getProperty(name)
         if (systemValue != null) {
             return systemValue
         }
 
-        val envValue = System.getenv(name)
+        val envValue: String? = System.getenv(name)
         if (envValue != null) {
             return envValue
         }