NullPointerException when Creating MCP Server on top of existing REST API with openAPIVersion v2

[DilkyLiyanage]

Description

No response

Steps to Reproduce

1. Create the backend REST API having openAPIVersion v2
2. Click Create API → Import Definition → Click Create.
3. Go to MCP Servers → Create MCP Server → Create MCP Server from Existing API.
4. Select the API you just created, click Next.
5. Select the one POST / operation as a tool, click Next.
6. Fill in Name/Context/Version, click Create.
7. Expect: a 500 error in the UI, and in wso2carbon.log a NullPointerException:

[2026-07-03 11:18:11,022] ERROR - GlobalThrowableMapper An unknown exception has been captured by the global exception mapper.
java.lang.NullPointerException: Cannot invoke "io.swagger.v3.oas.models.OpenAPI.getPaths()" because "backendDefinition" is null
at org.wso2.carbon.apimgt.spec.parser.definitions.OAS3Parser.generateMCPTools(OAS3Parser.java:2839)
at org.wso2.carbon.apimgt.rest.api.publisher.v1.common.mappings.PublisherCommonUtils.generateMCPFeatures(PublisherCommonUtils.java:4987)
at org.wso2.carbon.apimgt.rest.api.publisher.v1.common.mappings.PublisherCommonUtils.resolveExistingMCPBackendAPI(PublisherCommonUtils.java:2544)
at org.wso2.carbon.apimgt.rest.api.publisher.v1.common.mappings.PublisherCommonUtils.addAPIWithGeneratedSwaggerDefinition(PublisherCommonUtils.java:2439)
at org.wso2.carbon.apimgt.rest.api.publisher.v1.common.mappings.PublisherCommonUtils.addAPIWithGeneratedSwaggerDefinition(PublisherCommonUtils.java:2382)
at org.wso2.carbon.apimgt.rest.api.publisher.v1.impl.McpServersApiServiceImpl.createMCPServerFromAPI(McpServersApiServiceImpl.java:1423)
at org.wso2.carbon.apimgt.rest.api.publisher.v1.McpServersApi.createMCPServerFromAPI(McpServersApi.java:182)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:179)
at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:96)
at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:201)
at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:104)
at org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:59)
at org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:96)
at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:307)
at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:267)
at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:234)
at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:208)
at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:160)
at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:225)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:304)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doPost(AbstractHTTPServlet.java:217)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:555)
at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:279)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:197)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:142)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:166)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:88)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:491)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:83)
at org.wso2.carbon.identity.context.rewrite.valve.TenantContextRewriteValve.invoke(TenantContextRewriteValve.java:119)
at org.wso2.carbon.identity.context.rewrite.valve.OrganizationContextRewriteValve.invoke(OrganizationContextRewriteValve.java:115)
at org.wso2.carbon.tomcat.ext.valves.SameSiteCookieValve.invoke(SameSiteCookieValve.java:38)
at org.wso2.carbon.identity.authz.valve.AuthorizationValve.invoke(AuthorizationValve.java:167)
at org.wso2.carbon.identity.auth.valve.AuthenticationValve.invoke(AuthenticationValve.java:119)
at org.wso2.carbon.tomcat.ext.valves.CompositeValve.continueInvocation(CompositeValve.java:105)
at org.wso2.carbon.tomcat.ext.valves.TomcatValveContainer.invokeValves(TomcatValveContainer.java:49)
at org.wso2.carbon.tomcat.ext.valves.CompositeValve.invoke(CompositeValve.java:68)
at org.wso2.carbon.tomcat.ext.valves.CarbonStuckThreadDetectionValve.invoke(CarbonStuckThreadDetectionValve.java:152)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:764)
at org.wso2.carbon.tomcat.ext.valves.CarbonContextCreatorValve.invoke(CarbonContextCreatorValve.java:63)
at org.wso2.carbon.tomcat.ext.valves.RequestCorrelationIdValve.invoke(RequestCorrelationIdValve.java:137)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:72)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:344)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:398)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:1309)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1854)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:973)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:491)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63)
at java.base/java.lang.Thread.run(Thread.java:1583)

Version

4.7.0

Environment Details (with versions)

No response