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springgremlintinkergraph

How to fix 'java.lang.NoClassDefFoundError: org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversalSource$GraphTraversalSourceStub'?

I am trying to initialize an in-memory graph using TinkerGraph.

Firstly, i have defined the bean in my context xml file and tried to initialise the TinkerGraph.

My intention is to unit test the classes that i have created for forming the gremlin queries, the end queries that i get from these classes are in the form of a string, so in order to execute them through the TinkerGraph, i have the used the approach given in the following post: Get Gremlin query as a String and execute it in java without submitting it to the GremlinServer

I would also like to know whether the approach that i have taken is the preferred approach, for running the gremlin queries as part of the unit testing?

Following are the dependencies i have included in the pom.xml:

<dependency>
    <groupId>org.apache.tinkerpop</groupId>
    <artifactId>tinkergraph-gremlin</artifactId>
    <version>3.2.4</version>
</dependency>

<dependency>
      <groupId>org.apache.tinkerpop</groupId>
      <artifactId>gremlin-groovy</artifactId>
      <version>3.0.2-incubating</version>
</dependency>

EmbeddedGremlinQueryEngine is as follows:


import org.apache.tinkerpop.gremlin.driver.Result;
import org.apache.tinkerpop.gremlin.driver.ResultSet;
import org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerGraph;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.script.Bindings;
import javax.script.ScriptEngine;
import javax.script.ScriptException;
import java.util.List;

public class UcsEmbeddedGremlinQueryEngine implements GremlinEngine{

    private static final Logger logger = LoggerFactory.getLogger(UcsEmbeddedGremlinQueryEngine.class);
    private GraphTraversalSource graphTraversalSource = null;
    private Graph graph = null;
    private ScriptEngine engine = null;
    private Bindings bindings = null;

    public UcsEmbeddedGremlinQueryEngine() {
        graph = TinkerGraph.open();
        graphTraversalSource = graph.traversal();
        engine = new GremlinGroovyScriptEngine();
        bindings = engine.createBindings();
        bindings.put("g", graphTraversalSource);
    }

    public void shutdown() throws Exception {
        if (graph != null){
            graph.close();
        }
        logger.info("TinkerGraph shutdown complete.");
    }

    @Override
    public List<Result> query(String query) {
        List<Result> res = null;
        try {
            ResultSet results = (ResultSet) engine.eval(query, bindings);
            res = results.all().join();

            for (Result r : res) {
                System.out.println("result: " + r + '\n');
            }

        } catch (ScriptException e) {
            e.printStackTrace();
        }
        return res;
    }

    // This function reads the initScript and run them as gremlin queries.
    public synchronized void initialize() {
        logger.debug("Initializing embedded TinkerGraph. This will only take a few seconds....");
        //TODO include the execution of queries as part of initialisation
    }
}

Stack trace is as follows:

java.lang.NoClassDefFoundError: org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversalSource$GraphTraversalSourceStub
    at org.apache.tinkerpop.gremlin.groovy.loaders.StepLoader.load(StepLoader.groovy:54)
    at org.codehaus.groovy.vmplugin.v7.IndyInterface.selectMethod(IndyInterface.java:236)
    at org.apache.tinkerpop.gremlin.groovy.loaders.GremlinLoader.load(GremlinLoader.groovy:28)
    at org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine.<init>(GremlinGroovyScriptEngine.java:189)
    at org.apache.tinkerpop.gremlin.groovy.jsr223.GremlinGroovyScriptEngine.<init>(GremlinGroovyScriptEngine.java:172)
    at com.intuit.gro.mcsdata.gemlinengine.UcsEmbeddedGremlinQueryEngine.<init>(UcsEmbeddedGremlinQueryEngine.java:28)

EmbeddedGremlinQueryEngine is defined as a bean in the xml file, when the bean is loaded i get the error as Constructor threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/GraphTraversalSource$GraphTraversalSourceStub

I don't understand how the GraphTraversalSourceStub comes into picture during initialization, I was not able to find any information about it. Any help would be appreciated.

Solution

  • I think your problem is that you're:

    1. using really really old versions of TinkerPop
    2. the old versions you're using are probably incompatible

    I'm not sure if you have a reason for using 3.2.4, but if so, make sure gremlin-groovy is also 3.2.4. Note that the 3.2.x line of code is largely not maintained at this point with the last release being 3.2.11 about 6 months ago. If you are developing a new application then I highly recommend that you simply utilize the latest version of 3.4.2 which released a few weeks ago.

    As for your testing approach, I suppose that's fine. If you have test Gremlin strings then you really don't have much other choice in the matter, short of using Gremlin Server. Obviously providing a test harness for GremlinGroovyScriptEngine is a lot easier to do.