Fixed another leak in Java wrapper caused by listeners

wrappers/java/jni.mustache

@@ -357,28 +357,36 @@ static {{return}} {{callbackName}}({{params}}) {
 {{#interfaces}}
 {{#isSingleListener}}
 void Java_{{jniPackage}}{{className}}Impl_setListener(JNIEnv* env, jobject thiz, jlong ptr, jobject jlistener) {
+	{{classCName}} *cptr = ({{classCName}}*)ptr;
+	{{classCName}}Cbs *cbs = {{cPrefix}}_get_callbacks(cptr);
+	if (jlistener == NULL) {
+		jobject listener = (jobject) {{cPrefix}}_cbs_get_user_data(cbs);
+		{{cPrefix}}_cbs_set_user_data(cbs, NULL);
+		if (listener != NULL) {
+			env->DeleteGlobalRef(listener);
+		}
+	} else {
+		jobject listener = env->NewGlobalRef(jlistener);
+		{{cPrefix}}_cbs_set_user_data(cbs, listener);
+		{{#callbacksList}}
+		{{cPrefix}}_cbs_set_{{callback}}(cbs, {{callbackName}});
+		{{/callbacksList}}
+	}
+}
 {{/isSingleListener}}
+
 {{#isMultiListener}}
 void Java_{{jniPackage}}{{className}}Impl_addListener(JNIEnv* env, jobject thiz, jlong ptr, jobject jlistener) {
-{{/isMultiListener}}
 	{{classCName}} *cptr = ({{classCName}}*)ptr;
 	jobject listener = env->NewGlobalRef(jlistener);
-	{{#isSingleListener}}
-	{{classCName}}Cbs *cbs = {{cPrefix}}_get_callbacks(cptr);
-	{{/isSingleListener}}
-	{{#isMultiListener}}
 	{{classCName}}Cbs *cbs = linphone_factory_create_{{factoryName}}_cbs(NULL);
-	{{/isMultiListener}}
 	{{cPrefix}}_cbs_set_user_data(cbs, listener);
 	{{#callbacksList}}
 	{{cPrefix}}_cbs_set_{{callback}}(cbs, {{callbackName}});
 	{{/callbacksList}}
-	{{#isMultiListener}}
 	{{cPrefix}}_add_callbacks(cptr, cbs);
 	{{cPrefix}}_cbs_unref(cbs);
-	{{/isMultiListener}}
 }
-{{#isMultiListener}}
 
 void Java_{{jniPackage}}{{className}}Impl_removeListener(JNIEnv* env, jobject thiz, jlong ptr, jobject jlistener) {
 	{{classCName}} *cptr = ({{classCName}}*)ptr;
@@ -396,7 +404,6 @@ void Java_{{jniPackage}}{{className}}Impl_removeListener(JNIEnv* env, jobject th
 	}
 }
 {{/isMultiListener}}
-
 {{/interfaces}}
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////