[java] Fix template logic related to supportUrlQuery (#14496)

* [java] Fix template logic related to supportUrlQuery

Generated models for arrays marked with uniqueItems: true (which end up as a Set<> in java) won't
compile because the templates are in some places using .get(i) on the sets.

Also, when the supportUrlQuery property is present in the additionalProperties map the
resulting value will be read using the key SUPPORT_STREAMING instead of 'supportUrlQuery'.

* fix NPE

Co-authored-by: Björgvin <bjorgvino@gmail.com>

Author: wing328

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

@@ -68,6 +68,7 @@ public class JavaClientCodegen extends AbstractJavaCodegen
     public static final String USE_ABSTRACTION_FOR_FILES = "useAbstractionForFiles";
     public static final String DYNAMIC_OPERATIONS = "dynamicOperations";
     public static final String SUPPORT_STREAMING = "supportStreaming";
+    public static final String SUPPORT_URL_QUERY = "supportUrlQuery";
     public static final String GRADLE_PROPERTIES = "gradleProperties";
     public static final String ERROR_OBJECT_TYPE = "errorObjectType";
 
@@ -428,10 +429,13 @@ public void processOpts() {
         }
 
         // add URL query deepObject support to native, apache-httpclient by default
-        if (!additionalProperties.containsKey("supportUrlQuery") && (isLibrary(NATIVE) || isLibrary(APACHE))) {
-            additionalProperties.put("supportUrlQuery", true);
+        if (!additionalProperties.containsKey(SUPPORT_URL_QUERY)) {
+            if (isLibrary(NATIVE) || isLibrary(APACHE)) {
+                // default to true for native and apache-httpclient
+                additionalProperties.put(SUPPORT_URL_QUERY, true);
+            }
         } else {
-            additionalProperties.put("supportUrlQuery", Boolean.parseBoolean(additionalProperties.get(SUPPORT_STREAMING).toString()));
+            additionalProperties.put(SUPPORT_URL_QUERY, Boolean.parseBoolean(additionalProperties.get(SUPPORT_URL_QUERY).toString()));
         }
 
         final String invokerFolder = (sourceFolder + '/' + invokerPackage).replace(".", "/");

modules/openapi-generator/src/main/resources/Java/libraries/native/oneof_model.mustache

@@ -294,7 +294,7 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
         if (getActualInstance() != null) {
           int i = 0;
           for ({{items.dataType}} _item : ({{{dataType}}})getActualInstance()) {
-            if ((({{{dataType}}})getActualInstance()).get(i) != null) {
+            if (_item != null) {
               joiner.add(_item.toUrlQueryString(String.format("%s{{baseName}}%s%s", prefix, suffix,
                   "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix))));
             }

modules/openapi-generator/src/main/resources/Java/libraries/native/pojo.mustache

@@ -413,7 +413,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
     if ({{getter}}() != null) {
       int i = 0;
       for ({{items.dataType}} _item : {{getter}}()) {
-        if ({{getter}}().get(i) != null) {
+        if (_item != null) {
           joiner.add(_item.toUrlQueryString(String.format("%s{{baseName}}%s%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix))));
         }

modules/openapi-generator/src/main/resources/Java/pojo.mustache

@@ -411,7 +411,7 @@ public class {{classname}} {{#parent}}extends {{{.}}} {{/parent}}{{#vendorExtens
     if ({{getter}}() != null) {
       int i = 0;
       for ({{items.dataType}} _item : {{getter}}()) {
-        if ({{getter}}().get(i) != null) {
+        if (_item != null) {
           joiner.add(_item.toUrlQueryString(String.format("%s{{baseName}}%s%s", prefix, suffix,
               "".equals(suffix) ? "" : String.format("%s%d%s", containerPrefix, i, containerSuffix))));
         }