Delete unused method (#1744)

* Delete unused method

* Delete unused property "typeMapping"

* Delete unused "import" declaration

modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenModelFactory.java

@@ -18,36 +18,12 @@
 package org.openapitools.codegen;
 
 import java.lang.reflect.InvocationTargetException;
-import java.util.HashMap;
-import java.util.Map;
 
 public final class CodegenModelFactory {
-
-    private static final Map<CodegenModelType, Class<?>> typeMapping = new HashMap<CodegenModelType, Class<?>>();
-
-    /**
-     * Configure a different implementation class.
-     *
-     * @param type           the type that shall be replaced
-     * @param implementation the implementation class must extend the default class and must provide a public no-arg constructor
-     */
-    public static void setTypeMapping(CodegenModelType type, Class<?> implementation) {
-        if (!type.getDefaultImplementation().isAssignableFrom(implementation)) {
-            throw new IllegalArgumentException(implementation.getSimpleName() + " doesn't extend " + type.getDefaultImplementation().getSimpleName());
-        }
-        try {
-            implementation.getDeclaredConstructor().newInstance();
-        } catch (Exception e) {
-            throw new IllegalArgumentException(e);
-        }
-        typeMapping.put(type, implementation);
-    }
-
     @SuppressWarnings("unchecked")
     public static <T> T newInstance(CodegenModelType type) {
-        Class<?> classType = typeMapping.get(type);
         try {
-            return (T) (classType != null ? classType : type.getDefaultImplementation()).getDeclaredConstructor().newInstance();
+            return (T) type.getDefaultImplementation().getDeclaredConstructor().newInstance();
         } catch (IllegalAccessException | InstantiationException | NoSuchMethodException | InvocationTargetException e) {
             throw new RuntimeException(e);
         }