Groovy program to connect mongo db
<p>I am trying to connect mongodb using Groovy language but i am getting error like this (which is posted below) and i have added necessary jar file.I am using mongodb verion : mongodb-driver-3.2.2.jar .
Please help me to solve this problem</p>

<pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: com/mongodb/operation/OperationExecutor
    at java.lang.Class.getDeclaredConstructors0(Native Method)
    at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
    at java.lang.Class.getDeclaredConstructors(Unknown Source)
    at org.codehaus.groovy.reflection.CachedClass$2$1.run(CachedClass.java:69)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.codehaus.groovy.reflection.CachedClass$2.initValue(CachedClass.java:67)
    at org.codehaus.groovy.reflection.CachedClass$2.initValue(CachedClass.java:64)
    at org.codehaus.groovy.util.LazyReference.getLocked(LazyReference.java:46)
    at org.codehaus.groovy.util.LazyReference.get(LazyReference.java:33)
    at org.codehaus.groovy.reflection.CachedClass.getConstructors(CachedClass.java:258)
    at groovy.lang.MetaClassImpl.&lt;init&gt;(MetaClassImpl.java:213)
    at groovy.lang.MetaClassImpl.&lt;init&gt;(MetaClassImpl.java:223)
    at groovy.lang.MetaClassRegistry$MetaClassCreationHandle.createNormalMetaClass(MetaClassRegistry.java:168)
    at groovy.lang.MetaClassRegistry$MetaClassCreationHandle.createWithCustomLookup(MetaClassRegistry.java:158)
    at groovy.lang.MetaClassRegistry$MetaClassCreationHandle.create(MetaClassRegistry.java:141)
    at org.codehaus.groovy.reflection.ClassInfo.getMetaClassUnderLock(ClassInfo.java:209)
    at org.codehaus.groovy.reflection.ClassInfo.getMetaClass(ClassInfo.java:241)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.getMetaClass(MetaClassRegistryImpl.java:255)
    at org.codehaus.groovy.runtime.InvokerHelper.getMetaClass(InvokerHelper.java:859)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.createCallConstructorSite(CallSiteArray.java:84)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCallConstructor(CallSiteArray.java:57)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:182)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:194)
    at com.sample.MongoService.client(MongoService.groovy:14)
    at com.sample.MongoService.collection(MongoService.groovy:21)
    at com.sample.MongoService$collection.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:116)
    at com.sample.MongoDBController.method(MongoDBController.groovy:10)
    at com.sample.MongoDBController$method.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:45)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:108)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:112)
    at com.sample.GroovyDemoApp.main(GroovyDemoApp.groovy:12)
Caused by: java.lang.ClassNotFoundException: com.mongodb.operation.OperationExecutor
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    ... 35 more
</code></pre>

<p><strong>Update :</strong></p>

<p>This is my Groovy code. with this code i am trying to connect Mongodb</p>

<pre><code>// error is in this line . i .e - 
// The type com.mongodb.operation.CreateIndexesOperation cannot be resolved.
// It is indirectly referenced from required .class files )
package com.sample

import com.mongodb.*

class MongoService { 
  private static MongoClient mongoClient 
  private static host = "localhost" //your host name 
  private static port = 27017 //your port no. 
  private static databaseName = "db"

  public static MongoClient client() {
    if(mongoClient == null){
        return new MongoClient(host,port)
    }else {
        return mongoClient
    }
  }

  public DBCollection collection(collectionName) {
    DB db = client().getDB(databaseName)
    return db.getCollection(collectionName)
  }
}
</code></pre>