diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java
index 8016f516b456..ffd0c2848654 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java
@@ -229,6 +229,11 @@ public class DefaultCodegen {
     }
 
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         return operationId;
     }
 
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AkkaScalaClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AkkaScalaClientCodegen.java
index efcd771ac10d..f9490e3d3dd7 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AkkaScalaClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AkkaScalaClientCodegen.java
@@ -251,6 +251,11 @@ public class AkkaScalaClientCodegen extends DefaultCodegen implements CodegenCon
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         return super.toOperationId(CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_CAMEL, operationId));
     }
 
@@ -396,4 +401,4 @@ public class AkkaScalaClientCodegen extends DefaultCodegen implements CodegenCon
         }
     }
 
-}
\ No newline at end of file
+}
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AndroidClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AndroidClientCodegen.java
index e65736a63f04..f570cc42e821 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AndroidClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AndroidClientCodegen.java
@@ -13,6 +13,8 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class AndroidClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String invokerPackage = "io.swagger.client";
     protected String groupId = "io.swagger";
@@ -168,6 +170,11 @@ public class AndroidClientCodegen extends DefaultCodegen implements CodegenConfi
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AsyncScalaClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AsyncScalaClientCodegen.java
index c941d8b8d976..53faf2f9e1fc 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AsyncScalaClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AsyncScalaClientCodegen.java
@@ -21,6 +21,8 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class AsyncScalaClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String invokerPackage = "io.swagger.client";
     protected String groupId = "io.swagger";
@@ -204,4 +206,4 @@ public class AsyncScalaClientCodegen extends DefaultCodegen implements CodegenCo
             return "null";
         }
     }
-}
\ No newline at end of file
+}
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
index 5833d7287cc2..1d7accd3b274 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/CSharpClientCodegen.java
@@ -14,6 +14,8 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class CSharpClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String packageName = "IO.Swagger";
     protected String packageVersion = "1.0.0";
@@ -237,6 +239,11 @@ public class CSharpClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ObjcClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ObjcClientCodegen.java
index 3e5edbc169fd..887422cd490c 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ObjcClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ObjcClientCodegen.java
@@ -16,6 +16,8 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Set;
 
+import org.apache.commons.lang.StringUtils;
+
 public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected Set<String> foundationClasses = new HashSet<String>();
     protected String podName = "SwaggerClient";
@@ -358,6 +360,11 @@ public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PerlClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PerlClientCodegen.java
index 8c079973a1be..80f83bc2d102 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PerlClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PerlClientCodegen.java
@@ -9,11 +9,12 @@ import io.swagger.models.properties.MapProperty;
 import io.swagger.models.properties.Property;
 import io.swagger.codegen.CliOption;
 
-
 import java.io.File;
 import java.util.Arrays;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class PerlClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String moduleName = "SwaggerClient";
     protected String moduleVersion = "1.0.0";
@@ -213,6 +214,11 @@ public class PerlClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java
index 188e5c76644e..1b40cc0a30eb 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java
@@ -15,6 +15,8 @@ import java.util.Arrays;
 import java.util.HashMap;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class PhpClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String invokerPackage = "Swagger\\Client";
     protected String composerVendorName = "swagger";
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/Python3ClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/Python3ClientCodegen.java
index 71562e6ba370..70c090cd7a3b 100755
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/Python3ClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/Python3ClientCodegen.java
@@ -12,6 +12,8 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class Python3ClientCodegen extends DefaultCodegen implements CodegenConfig {
     String module = "client";
 
@@ -201,6 +203,11 @@ public class Python3ClientCodegen extends DefaultCodegen implements CodegenConfi
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java
index 8f78f2e1d490..e0e1bdc07f8d 100755
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PythonClientCodegen.java
@@ -13,6 +13,8 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String packageName = null;
     protected String packageVersion = null;
@@ -246,6 +248,11 @@ public class PythonClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RetrofitClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RetrofitClientCodegen.java
index e043c68baf9e..66d3f19f948b 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RetrofitClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RetrofitClientCodegen.java
@@ -15,6 +15,8 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.lang.StringUtils;
+
 public class RetrofitClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String invokerPackage = "io.swagger.client";
     protected String groupId = "io.swagger";
@@ -171,6 +173,11 @@ public class RetrofitClientCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RubyClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RubyClientCodegen.java
index 716c1bb08708..36a3f31aa486 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RubyClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/RubyClientCodegen.java
@@ -13,6 +13,8 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class RubyClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String gemName = null;
     protected String moduleName = null;
@@ -267,6 +269,11 @@ public class RubyClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ScalaClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ScalaClientCodegen.java
index 6ad296a02103..5d8ae4b89b63 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ScalaClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/ScalaClientCodegen.java
@@ -24,6 +24,8 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.commons.lang.StringUtils;
+
 public class ScalaClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected String invokerPackage = "io.swagger.client";
     protected String groupId = "io.swagger";
@@ -209,6 +211,11 @@ public class ScalaClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java
index 44cf978eb1dc..5bc402fe0c47 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SinatraServerCodegen.java
@@ -13,6 +13,8 @@ import java.io.File;
 import java.util.Arrays;
 import java.util.HashSet;
 
+import org.apache.commons.lang.StringUtils;
+
 public class SinatraServerCodegen extends DefaultCodegen implements CodegenConfig {
     protected String gemName = null;
     protected String moduleName = null;
diff --git a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/TizenClientCodegen.java b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/TizenClientCodegen.java
index 34305d7c56f7..7dc0b8ec3bd8 100644
--- a/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/TizenClientCodegen.java
+++ b/modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/TizenClientCodegen.java
@@ -25,6 +25,8 @@ import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 
+import org.apache.commons.lang.StringUtils;
+
 public class TizenClientCodegen extends DefaultCodegen implements CodegenConfig {
     protected static String PREFIX = "Sami";
     protected Set<String> foundationClasses = new HashSet<String>();
@@ -265,6 +267,11 @@ public class TizenClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String toOperationId(String operationId) {
+        // throw exception if method name is empty
+        if (StringUtils.isEmpty(operationId)) {
+            throw new RuntimeException("Empty method name (operationId) not allowed");
+        }
+
         // method name cannot use reserved keyword, e.g. return$
         if (reservedWords.contains(operationId)) {
             throw new RuntimeException(operationId + " (reserved word) cannot be used as method name");