diff --git a/cli/src/main/java/hudson/util/QuotedStringTokenizer.java b/cli/src/main/java/hudson/util/QuotedStringTokenizer.java
index 665126f1cc..6b8a6f43f7 100644
--- a/cli/src/main/java/hudson/util/QuotedStringTokenizer.java
+++ b/cli/src/main/java/hudson/util/QuotedStringTokenizer.java
@@ -269,6 +269,9 @@ public class QuotedStringTokenizer
                   else
                       _token.append(c);
                   continue;
+
+              default:
+                  break;
             }
         }
 
diff --git a/core/src/main/java/hudson/cli/ListChangesCommand.java b/core/src/main/java/hudson/cli/ListChangesCommand.java
index b282459b17..618e4d9334 100644
--- a/core/src/main/java/hudson/cli/ListChangesCommand.java
+++ b/core/src/main/java/hudson/cli/ListChangesCommand.java
@@ -88,6 +88,8 @@ public class ListChangesCommand extends RunRangeCommand {
                 }
             }
             break;
+        default:
+            throw new AssertionError("Unknown format: " + format);
         }
 
         return 0;
diff --git a/core/src/main/java/hudson/console/ConsoleAnnotator.java b/core/src/main/java/hudson/console/ConsoleAnnotator.java
index a5c866a5a2..9761439320 100644
--- a/core/src/main/java/hudson/console/ConsoleAnnotator.java
+++ b/core/src/main/java/hudson/console/ConsoleAnnotator.java
@@ -126,9 +126,8 @@ public abstract class ConsoleAnnotator<T> implements Serializable {
         switch (all.size()) {
         case 0:     return null;    // none
         case 1:     return  cast(all.iterator().next()); // just one
+        default:    return new ConsoleAnnotatorAggregator<>(all);
         }
-
-        return new ConsoleAnnotatorAggregator<>(all);
     }
 
     /**
diff --git a/core/src/main/java/hudson/model/Run.java b/core/src/main/java/hudson/model/Run.java
index 0923563af6..55ad30782b 100644
--- a/core/src/main/java/hudson/model/Run.java
+++ b/core/src/main/java/hudson/model/Run.java
@@ -2233,9 +2233,9 @@ public abstract class Run <JobT extends Job<JobT,RunT>,RunT extends Run<JobT,Run
             case FIXED :
                 return new Summary(false, Messages.Run_Summary_BackToNormal());
                 
+            default:
+                return new Summary(false, Messages.Run_Summary_Unknown());
         }
-        
-        return new Summary(false, Messages.Run_Summary_Unknown());
     }
 
     /**
diff --git a/core/src/main/java/hudson/model/UpdateCenter.java b/core/src/main/java/hudson/model/UpdateCenter.java
index 42eb633778..da936be626 100644
--- a/core/src/main/java/hudson/model/UpdateCenter.java
+++ b/core/src/main/java/hudson/model/UpdateCenter.java
@@ -2086,6 +2086,8 @@ public class UpdateCenter extends AbstractModelObject implements Saveable, OnMas
                 throw new IOException("Failed to compute SHA-1 of downloaded file, refusing installation");
             case NOT_PROVIDED:
                 throw new IOException("Unable to confirm integrity of downloaded file, refusing installation");
+            default:
+                throw new AssertionError("Unknown verification result: " + result1);
         }
     }
 
diff --git a/core/src/main/java/hudson/util/jna/RegistryKey.java b/core/src/main/java/hudson/util/jna/RegistryKey.java
index aa676b8fa4..f0d7280766 100644
--- a/core/src/main/java/hudson/util/jna/RegistryKey.java
+++ b/core/src/main/java/hudson/util/jna/RegistryKey.java
@@ -105,8 +105,10 @@ public class RegistryKey implements AutoCloseable {
 
             case WINERROR.ERROR_SUCCESS:
                 return lpData;
+
+            default:
+                throw new JnaException(r);
             }
-            throw new JnaException(r);
         }
     }
 
diff --git a/core/src/main/java/jenkins/tasks/filters/impl/RetainVariablesLocalRule.java b/core/src/main/java/jenkins/tasks/filters/impl/RetainVariablesLocalRule.java
index f22deec842..ee867332cf 100644
--- a/core/src/main/java/jenkins/tasks/filters/impl/RetainVariablesLocalRule.java
+++ b/core/src/main/java/jenkins/tasks/filters/impl/RetainVariablesLocalRule.java
@@ -155,6 +155,8 @@ public class RetainVariablesLocalRule implements EnvVarsFilterLocalRule {
                             variablesRemoved.add(variableName);
                             iterator.remove();
                             break;
+                        default:
+                            throw new AssertionError("Unknown process variables handling: " + processVariablesHandling);
                     }
                 }
             }
diff --git a/core/src/main/java/jenkins/util/JSONSignatureValidator.java b/core/src/main/java/jenkins/util/JSONSignatureValidator.java
index 2c6ffac991..274c0cb96c 100644
--- a/core/src/main/java/jenkins/util/JSONSignatureValidator.java
+++ b/core/src/main/java/jenkins/util/JSONSignatureValidator.java
@@ -105,7 +105,9 @@ public class JSONSignatureValidator {
                         LOGGER.log(Level.INFO, "JSON data source '" + name + "' does not provide a SHA-512 content checksum or signature. Looking for SHA-1.");
                         break;
                     case OK:
-                        // fall through
+                        break;
+                    default:
+                        throw new AssertionError("Unknown form validation kind: " + resultSha512.kind);
                 }
             } catch (NoSuchAlgorithmException nsa) {
                 LOGGER.log(Level.WARNING, "Failed to verify potential SHA-512 digest/signature, falling back to SHA-1", nsa);
@@ -127,7 +129,9 @@ public class JSONSignatureValidator {
                         return FormValidation.error("No correct_signature or correct_signature512 entry found in '" + name + "'.");
                     }
                 case OK:
-                    // fall through
+                    break;
+                default:
+                    throw new AssertionError("Unknown form validation kind: " + resultSha1.kind);
             }
 
             if (warning!=null)  return warning;
diff --git a/core/src/main/java/org/jenkins/ui/icon/IconType.java b/core/src/main/java/org/jenkins/ui/icon/IconType.java
index 5c80acf990..54b2cdba33 100644
--- a/core/src/main/java/org/jenkins/ui/icon/IconType.java
+++ b/core/src/main/java/org/jenkins/ui/icon/IconType.java
@@ -54,8 +54,8 @@ public enum IconType {
             case PLUGIN: {
                 return resURL + "/plugin/" + url;
             }
+            default:
+                throw new AssertionError("Unknown icon type: " + this);
         }
-
-        return null;
     }
 }
diff --git a/pom.xml b/pom.xml
index 05053de07f..51cafc5d70 100644
--- a/pom.xml
+++ b/pom.xml
@@ -454,6 +454,7 @@ THE SOFTWARE.
                   <module name="CovariantEquals" />
                   <module name="DefaultComesLast" />
                   <module name="EqualsHashCode" />
+                  <module name="MissingSwitchDefault" />
                   <module name="NoEnumTrailingComma" />
                   <module name="OneStatementPerLine" />
                   <module name="PackageDeclaration" />