diff --git a/src/main/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinition.java b/src/main/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinition.java
index 8454766..73f66c3 100644
--- a/src/main/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinition.java
+++ b/src/main/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinition.java
@@ -86,7 +86,7 @@ public class GitParameterDefinition extends ParameterDefinition implements Compa
     public static boolean allowAnyParameterValue =
             SystemProperties.getBoolean(ALLOW_ANY_PARAMETER_VALUE_PROPERTY_NAME, false);
 
-    private final UUID uuid;
+    private UUID uuid;
     private String type;
     private String branch;
     private String tagFilter;
@@ -128,6 +128,15 @@ public GitParameterDefinition(
         setBranchFilter(branchFilter);
     }
 
+    private Object readResolve() {
+        // Jobs created before UUID was introduced can deserialize with a null UUID.
+        // Assign one to preserve stable identity matching and prevent null handling bugs.
+        if (uuid == null) {
+            uuid = UUID.randomUUID();
+        }
+        return this;
+    }
+
     @Override
     public ParameterValue createValue(StaplerRequest2 request) {
         String value[] = request.getParameterValues(getName());
@@ -323,7 +332,13 @@ public Boolean getQuickFilterEnabled() {
 
     @Override
     public int compareTo(GitParameterDefinition pd) {
-        return pd.uuid.equals(uuid) ? 0 : -1;
+        if (pd == null) {
+            return -1;
+        }
+        if (this == pd) {
+            return 0;
+        }
+        return uuid != null && pd.uuid != null && pd.uuid.equals(uuid) ? 0 : -1;
     }
 
     /* Set of values allowed for this parameter definition */
diff --git a/src/test/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinitionTest.java b/src/test/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinitionTest.java
index ca8cb61..8856f92 100644
--- a/src/test/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinitionTest.java
+++ b/src/test/java/net/uaznia/lukanus/hudson/plugins/gitparameter/GitParameterDefinitionTest.java
@@ -27,9 +27,11 @@
 import hudson.tasks.Shell;
 import hudson.util.FormValidation;
 import hudson.util.FormValidation.Kind;
+import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.UUID;
 import net.sf.json.JSONObject;
 import net.uaznia.lukanus.hudson.plugins.gitparameter.GitParameterDefinition.DescriptorImpl;
 import net.uaznia.lukanus.hudson.plugins.gitparameter.jobs.JobWrapper;
@@ -54,6 +56,12 @@
 @WithJenkins
 class GitParameterDefinitionTest {
 
+    private static void setUuid(GitParameterDefinition definition, UUID uuid) throws Exception {
+        Field uuidField = GitParameterDefinition.class.getDeclaredField("uuid");
+        uuidField.setAccessible(true);
+        uuidField.set(definition, uuid);
+    }
+
     // Test Descriptor.getProjectSCM()
     @Test
     void testGetProjectSCM(JenkinsRule jenkins) throws Exception {
@@ -466,6 +474,62 @@ void testSearchInFolders(JenkinsRule jenkins) throws Exception {
         assertEquals("folder/job1", Utils.getParentJob(gitParameterDefinition).getFullName());
     }
 
+    @Test
+    void testSearchInFoldersWithNullUuid(JenkinsRule jenkins) throws Exception {
+        MockFolder folder = jenkins.createFolder("folder");
+        FreeStyleProject job1 = folder.createProject(FreeStyleProject.class, "job1");
+
+        GitParameterDefinition gitParameterDefinition = new GitParameterDefinition(
+                NAME,
+                "asdf",
+                "other",
+                "description",
+                "branch",
+                ".*",
+                "*",
+                SortMode.NONE,
+                SelectedValue.NONE,
+                null,
+                false);
+
+        setUuid(gitParameterDefinition, null);
+        job1.addProperty(new ParametersDefinitionProperty(gitParameterDefinition));
+        assertEquals("folder/job1", Utils.getParentJob(gitParameterDefinition).getFullName());
+    }
+
+    @Test
+    void testCompareToWithNullUuidDoesNotThrow() throws Exception {
+        GitParameterDefinition left = new GitParameterDefinition(
+                "left",
+                PT_BRANCH,
+                "origin/develop",
+                "description",
+                "origin/develop",
+                ".*",
+                "*",
+                SortMode.NONE,
+                SelectedValue.NONE,
+                null,
+                false);
+        GitParameterDefinition right = new GitParameterDefinition(
+                "right",
+                PT_BRANCH,
+                "origin/develop",
+                "description",
+                "origin/develop",
+                ".*",
+                "*",
+                SortMode.NONE,
+                SelectedValue.NONE,
+                null,
+                false);
+
+        setUuid(right, null);
+
+        assertEquals(-1, left.compareTo(right));
+        assertEquals(0, right.compareTo(right));
+    }
+
     @Test
     void testBranchFilterValidation(JenkinsRule jenkins) {
         final DescriptorImpl descriptor = new DescriptorImpl();