diff --git a/src/main/java/org/jenkins/plugins/lockableresources/LockStep.java b/src/main/java/org/jenkins/plugins/lockableresources/LockStep.java
index 42ec37760..4742958e0 100644
--- a/src/main/java/org/jenkins/plugins/lockableresources/LockStep.java
+++ b/src/main/java/org/jenkins/plugins/lockableresources/LockStep.java
@@ -3,6 +3,7 @@
 import edu.umd.cs.findbugs.annotations.CheckForNull;
 import edu.umd.cs.findbugs.annotations.NonNull;
 import edu.umd.cs.findbugs.annotations.Nullable;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import hudson.Extension;
 import hudson.model.AutoCompletionCandidates;
 import hudson.model.Item;
@@ -32,24 +33,32 @@ public class LockStep extends Step implements Serializable {
     private static final long serialVersionUID = -953609907239674360L;
 
     @CheckForNull
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public String resource = null;
 
     @CheckForNull
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public String label = null;
 
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public int quantity = 0;
 
     /** name of environment variable to store locked resources in */
     @CheckForNull
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public String variable = null;
 
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public boolean inversePrecedence = false;
 
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public String resourceSelectStrategy = ResourceSelectStrategy.SEQUENTIAL.name();
 
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public boolean skipIfLocked = false;
 
     @CheckForNull
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public List<LockStepResource> extra = null;
 
     // it should be LockStep() - without params. But keeping this for backward compatibility
diff --git a/src/main/java/org/jenkins/plugins/lockableresources/LockStepResource.java b/src/main/java/org/jenkins/plugins/lockableresources/LockStepResource.java
index 343d7968e..c78373052 100644
--- a/src/main/java/org/jenkins/plugins/lockableresources/LockStepResource.java
+++ b/src/main/java/org/jenkins/plugins/lockableresources/LockStepResource.java
@@ -3,6 +3,7 @@
 import edu.umd.cs.findbugs.annotations.CheckForNull;
 import edu.umd.cs.findbugs.annotations.NonNull;
 import edu.umd.cs.findbugs.annotations.Nullable;
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import hudson.Extension;
 import hudson.Util;
 import hudson.model.AbstractDescribableImpl;
@@ -28,8 +29,10 @@ public class LockStepResource extends AbstractDescribableImpl<LockStepResource>
     public String resource = null;
 
     @CheckForNull
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public String label = null;
 
+    @SuppressFBWarnings(value = "PA_PUBLIC_PRIMITIVE_ATTRIBUTE", justification = "Preserve API compatibility.")
     public int quantity = 0;
 
     LockStepResource(@Nullable String resource, @Nullable String label, int quantity) {
diff --git a/src/main/java/org/jenkins/plugins/lockableresources/RequiredResourcesProperty.java b/src/main/java/org/jenkins/plugins/lockableresources/RequiredResourcesProperty.java
index fc24b3e5a..0248d6d34 100644
--- a/src/main/java/org/jenkins/plugins/lockableresources/RequiredResourcesProperty.java
+++ b/src/main/java/org/jenkins/plugins/lockableresources/RequiredResourcesProperty.java
@@ -270,8 +270,13 @@ public AutoCompletionCandidates doAutoCompleteLabelName(
 
             value = Util.fixEmptyAndTrim(value);
 
-            if (value != null) {
-                for (String l : LockableResourcesManager.get().getAllLabels()) if (l.startsWith(value)) c.add(l);
+            if (value == null) {
+                return c;
+            }
+            for (String l : LockableResourcesManager.get().getAllLabels()) {
+                if (l.startsWith(value)) {
+                    c.add(l);
+                }
             }
 
             return c;
@@ -287,10 +292,13 @@ public static AutoCompletionCandidates doAutoCompleteResourceNames(
 
             value = Util.fixEmptyAndTrim(value);
 
-            if (value != null) {
-                List<String> allNames = LockableResourcesManager.get().getAllResourcesNames();
-                for (String name : allNames) {
-                    if (name.startsWith(value)) c.add(name);
+            if (value == null) {
+                return c;
+            }
+            List<String> allNames = LockableResourcesManager.get().getAllResourcesNames();
+            for (String name : allNames) {
+                if (name.startsWith(value)) {
+                    c.add(name);
                 }
             }