Question Re: About CAP for Java errors in Technology Q&A

About CAP for Java errors

former_member757411 — Wed, 11 Aug 2021 12:19:34 GMT

Dear Experts,

I'm getting the following error, but I'm in trouble because I don't know how to deal with it ...

Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception
[Handler dispath failed; nested exception is java.lang.NoSuchMethodError;
'com.sap.cloud.sdk.datamodel.odata.client.expression.FieldUntyped com.sap.cloud.sdk.datamodel.odata.cli
ent.expression.FieldReference.ofPath(java.lang.Striong[])'] with root cause

Timing:

This error is occurring in the Read process of the @On event. Correctly, "remote.run (selectQuery);" that is executed inside the Read process

There was an error in.

I'm not familiar with Java, so I'd appreciate it if you could tell me a little more about how to do it.

Regards,

rinn.

Re: About CAP for Java errors

marcbecker — Wed, 11 Aug 2021 12:52:03 GMT

This is most likely a dependency issue. It seems like you are referencing a Cloud SDK version that is not compatible with the CAP Java version you are using. Please have a look at our public sample which always shows our recommended version combination: https://github.com/SAP-samples/cloud-cap-samples-java/blob/main/pom.xml#L19-L21

Re: About CAP for Java errors

former_member757411 — Tue, 17 Aug 2021 07:56:14 GMT

Sorry for my late reply.

I was able to solve the local error here!

However, there is another problem.

First, the data cannot be acquired. 0 results will be returned as a search result ...

Second, I get an error in the deployed application. The content was logged as "Caused by: com.sap.cds.CdsDataStoreException: Error executing the statement".

If you like, I would appreciate your advice on this as well ...

By the way, the URL you are referring to is here.

https://bnheise.medium.com/sap-tutorial-serving-data-from-an-on-premise-system-in-a-cap-java-application-part-1-2426175ad4fa

Re: About CAP for Java errors

marcbecker — Tue, 17 Aug 2021 09:38:16 GMT

Can you please provide the full exception stacktrace for the error "Caused by: com.sap.cds.CdsDataStoreException: Error executing the statement"?

Re: About CAP for Java errors

former_member757411 — Tue, 17 Aug 2021 10:25:00 GMT

errorlog.txt

Thank you for your reply. Attach the error log. I was checking and thought, but is there a table in the DB? Was also seen. Since the attached URL refers to S / 4 (On Premise) data, I have not added the table to the DB on HANA Cloud. Is this necessary? I'm sorry to ask you various questions ...

Re: About CAP for Java errors

marcbecker — Tue, 17 Aug 2021 13:37:51 GMT

CAP by default always try to read data from the Database using the PersistenceService. This is also what happens in your case and runs into an error as the database table is not available. If you want to read the data from somewhere else (e.g. the S/4 system) you need to explicitly forward the query to the S/4 system. You might want to look into Remote Services for this: https://cap.cloud.sap/docs/java/remote-services

Re: About CAP for Java errors

former_member757411 — Wed, 18 Aug 2021 10:16:12 GMT

Thank you for posting the link. I tried the contents of the remote service of the link.

However, there was no change in the error. (Contents that require Persistence Service) What else is missing?

The following is the contents of each file. (Pom.xml has been added as described in the link.)

application.yaml

---
spring:
  config.activate.on-profile: default
  datasource:
    url: "jdbc:sqlite:file::memory:?cache=shared"
    driver-class-name: org.sqlite.JDBC
    hikari:
      maximum-pool-size: 1
  sql:
    init:
      mode: always
cds:
  application.services:
    - name: "OnPremiseService"
      model: "Entity1_SRV"
  remote.services:
    - name: "Entity1_SRV"
      destination:
        name: "dest"
        type: "odata-v2"
        suffix: "/sap/opu/odata/sap"
---
spring:
  config.activate.on-profile: cloud
cds:
  remote.services:
    - name: "Entity1_SRV"
      destination:
        name: "dest"
        type: "odata-v2"
        suffix: "/sap/opu/odata/sap"

OnPremiseService.java

package com.sap.cap.productsservice.handlers;


import org.springframework.stereotype.Component;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;


import com.sap.cds.services.handler.annotations.ServiceName;
import com.sap.cds.services.handler.annotations.On;
import com.sap.cds.services.cds.CdsReadEventContext;
import com.sap.cds.services.handler.EventHandler;
import com.sap.cds.Result;
import com.sap.cds.ql.Select;
import com.sap.cds.ql.cqn.CqnSelect;
import com.sap.cds.services.cds.CqnService;
import com.sap.cds.services.cds.CdsService;


import cds.gen.Entity1_srv.*;


@Component
@ServiceName("OnPremiseService")
public class OnPremiseService implements EventHandler {
    @Autowired
    @Qualifier(Entity1Srv_.CDS_NAME)
    CqnService remote1;


    @On(event = CdsService.EVENT_READ, entity = Entity1_.CDS_NAME)
    public void onRead(CdsReadEventContext context) {
        CqnSelect selectQuery = Select.from(Entity1_.CDS_NAME);
        Result result = remote1.run(selectQuery);
        context.setResult(result);
    }


}

Re: About CAP for Java errors

marcbecker — Wed, 18 Aug 2021 11:28:15 GMT

Can you please attach the pom.xml where you added the cds-feature-remote-odata dependency?
Please also provide the stacktrace of the error you are getting this time, so that I can have a detailed look.

Re: About CAP for Java errors

former_member757411 — Wed, 18 Aug 2021 13:10:16 GMT

Thank you.

Pom(root) are attached below.

The error log and Pom.xml (srv) did not fit, so I will attach it as text.

Pom.xml(root)

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">;
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.sap.cap</groupId>
    <artifactId>capforjavaapp-parent</artifactId>
    <version>${revision}</version>
    <packaging>pom</packaging>

    <name>capforjavaapp parent</name>

    <properties>
        <!-- OUR VERSION -->
        <revision>1.0.0-SNAPSHOT</revision>

        <!-- DEPENDENCIES VERSION -->
        <jdk.version>1.8</jdk.version>
        <cds.services.version>1.17.0</cds.services.version>
        <spring.boot.version>2.5.2</spring.boot.version>
        <cloud.sdk.version>3.46.0</cloud.sdk.version>

        <node.url>https://nodejs.org/dist/</node.url>
    </properties>

    <modules>
        <module>srv</module>
    </modules>

    <dependencyManagement>
        <dependencies>
            <!-- CDS SERVICES -->
            <dependency>
                <groupId>com.sap.cds</groupId>
                <artifactId>cds-services-bom</artifactId>
                <version>${cds.services.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- SPRING BOOT -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring.boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <!-- CLOUD SDK --> 
            <dependency> 
                <groupId>com.sap.cloud.sdk</groupId> 
                <artifactId>sdk-bom</artifactId> 
                <version>${cloud.sdk.version}</version > 
                <type>pom</type> 
                <scope>import</scope> 
            </dependency>         

        </dependencies>        
    </dependencyManagement>

    <build>
        <plugins>
            <!-- JAVA VERSION -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>${jdk.version}</source>
                    <target>${jdk.version}</target>
                </configuration>
            </plugin>

            <!-- MAKE SPRING BOOT PLUGIN RUNNABLE FROM ROOT -->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <version>${spring.boot.version}</version>
                <configuration>
                    <skip>true</skip>
                </configuration>
            </plugin>

            <!-- POM FLATTENING FOR CI FRIENDLY VERSIONS -->
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>flatten-maven-plugin</artifactId>
                <version>1.2.5</version>
                <configuration>
                    <updatePomFile>true</updatePomFile>
                    <flattenMode>resolveCiFriendliesOnly</flattenMode>
                </configuration>
                <executions>
                    <execution>
                        <id>flatten</id>
                        <phase>process-resources</phase>
                        <goals>
                            <goal>flatten</goal>
                        </goals>
                    </execution>
                    <execution>
                        <id>flatten.clean</id>
                        <phase>clean</phase>
                        <goals>
                            <goal>clean</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>

            <!-- PROJECT STRUCTURE CHECKS -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-enforcer-plugin</artifactId>
                <version>3.0.0-M3</version>
                <executions>
                    <execution>
                        <id>Project Structure Checks</id>
                        <goals>
                            <goal>enforce</goal>
                        </goals>
                        <configuration>
                            <rules>
                                <requireMavenVersion>
                                    <version>3.5.0</version>
                                </requireMavenVersion>
                                <requireJavaVersion>
                                    <version>${jdk.version}</version>
                                </requireJavaVersion>
                                <reactorModuleConvergence />
                            </rules>
                            <fail>true</fail>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

Re: About CAP for Java errors

marcbecker — Wed, 18 Aug 2021 13:23:43 GMT

Thanks for the details. Everything looks fine in there. From the error stacktrace I can see however that your custom event handler that you implemented above that forwards the CQN statement to the remote service is not triggered.

Is the event handler in the same package or a sub-package as the Spring Boot Application.java class?
If not, the event handler will not be found during startup by Spring Boots automatic component scan.
Please move the event handler in that case to such a package.

If you think everything is correct and it still doesn't work, please provide the startup logs of the application.
I would like to check if we can see that the event handler is being detected in these logs.

Re: About CAP for Java errors

former_member757411 — Wed, 18 Aug 2021 13:52:46 GMT

Thank you for your confirmation.

Details will be attached. If the method of checking the startup log is incorrect,

I would appreciate it if you could tell me how to check it.

Re: About CAP for Java errors

former_member757411 — Wed, 18 Aug 2021 13:56:56 GMT

folder structure

Re: About CAP for Java errors

marcbecker — Wed, 18 Aug 2021 15:33:30 GMT

The folder structure looks also fine. The logs you attached unfortunately don't show the application startup.
If you test the application in the cloud please run "cf restart <appname>" and provide the recent logs afterwards.
If you start the application locally, please simply provide the output that it generates when starting.

Re: About CAP for Java errors

former_member757411 — Thu, 19 Aug 2021 01:43:29 GMT

Thank you for checking the folder structure.

Also, thank you for teaching me how to check the startup log.

This is the startup log.

Re: About CAP for Java errors

marcbecker — Thu, 19 Aug 2021 07:28:11 GMT

Hm, also here everything looks fine. Both services and handlers that I would expect are registered.
Would it be possible to upload your project somewhere (e.g. git repo) so that I can download it and try to reproduce the issue myself locally?

Re: About CAP for Java errors

former_member757411 — Thu, 19 Aug 2021 12:34:01 GMT

Thank you for making sure. I uploaded the source to github. However, due to the nature of the project, some modifications and deletions have been made. * S / 4 (On-Premise) connection related, etc.

If you have any questions, please let us know.

https://github.com/rinn-yamada/ztest

Re: About CAP for Java errors

marcbecker — Thu, 19 Aug 2021 13:24:56 GMT

Thanks for sharing. I finally figured out why the request doesn't go into your event handler. The reason is that your event handler for "OnPremiseService" register on entities from "Entity1_SRV" by using the entity interfaces from that service (see here and here). However "OnPremiseService" is not using the "Entity1_SRV", but has its own model definition "OnPremiseService" (see here). Therefore you should also use the entities from that definition to register event handlers, e.g. by changing "import cds.gen.entity1_srv.*;" to "import cds.gen.onpremiseservice.*"

An alternative would be to create the "OnPremiseService" with the model definition of "Entity1_SRV", as you did for the "OnPreService" in the default profile (see here)

Re: About CAP for Java errors

former_member757411 — Thu, 19 Aug 2021 14:58:40 GMT

Thank you for your prompt response.

It means that the service settings etc. were wrong ...

S / 4 is not ready to boot, so I'd like to try it tomorrow!

In addition, we will report the results. Thank you very much!

Re: About CAP for Java errors

former_member757411 — Fri, 20 Aug 2021 05:52:32 GMT

Does the method I modified fit in below?

1. changing "import cds.gen.entity1_srv.*;" to "import cds.gen.onpremiseservice.*"

onpremiseservicejava.txt

Re: About CAP for Java errors

former_member757411 — Fri, 20 Aug 2021 05:53:25 GMT

2. An alternative would be to create the "OnPremiseService" with the model definition of "Entity1_SRV", as you did for the "OnPreService" in the default profile

applicationyaml.txt

onpremiseservicejava2.txt