title: Get a lot of errors (Exceptions) while trying to call Java-classes (Neo4j) with JPype
body: <p>I'm trying to work with Java and Python Bridge JPype, but also with Neo4j (which is a graph database). When I try to run a simple Java-Program with JPYPE, there are no Problems.</p>
  
  <pre><code>import jpype as jp
  
  jp.startJVM(jp.getDefaultJVMPath(), "-ea")
  javaClass = jp.JClass('Jpype_test.A2')
  javaInstance = javaClass()
  javaInstance.callMe(2, 3)
  jp.shutdownJVM()
  </code></pre>
  
  <p>And the class in Java is just: </p>
  
  <pre><code>package Jpype_test;
  
  import helloworld.EmbeddedNeo4j;
  
  import java.io.IOException;
  
  public class A2 {
      public A2() {
          super();
  
      }
  
      public String callMe(final int a, final int b) throws IOException {
          final int res = Math.abs(a - b);
          try {
              EmbeddedNeo4j.main(null);
          } finally {
              System.out.println("I can't do this!");
          }
  
          return ("Hello, World!" + res);
      }
  }
  </code></pre>
  
  <p>But when I try to run the "same" HelloWorld-Program written including Neo4j, there are a lot of Errors and I don't really understand what I'm doing wrong.</p>
  
  <pre><code>package helloworld;
  
  import java.io.File;
  import java.io.IOException;
  
  import org.neo4j.graphdb.Direction;
  import org.neo4j.graphdb.GraphDatabaseService;
  import org.neo4j.graphdb.Node;
  import org.neo4j.graphdb.Relationship;
  import org.neo4j.graphdb.RelationshipType;
  import org.neo4j.graphdb.Transaction;
  import org.neo4j.graphdb.factory.GraphDatabaseFactory;
  import org.neo4j.io.fs.FileUtils;
  
  public class helloworld {
  
  private static final String db_path = "target/neo4j-hello-db";
  
  public String greeting;
  
  GraphDatabaseService graphdb;
  Node firstNode;
  Node secondNode;
  Relationship rs;
  
  private static enum RelTypes implements RelationshipType {
      KNOWS
  }
  
  public static void main(final String[] args) throws IOException {
      final helloworld hello = new helloworld();
      hello.createDb();
      hello.removeData();
      hello.shutDown();
  
  }
  
  void createDb() throws IOException {
      FileUtils.deleteRecursively(new File(db_path));
      graphdb = new GraphDatabaseFactory().newEmbeddedDatabase(db_path);
      registerShutdownHook(graphdb);
  
      try (Transaction tx = graphdb.beginTx()) {
          firstNode = graphdb.createNode();
          firstNode.setProperty("message", "Hello, ");
          secondNode = graphdb.createNode();
          secondNode.setProperty("message", "World!");
  
          rs = firstNode.createRelationshipTo(secondNode, RelTypes.KNOWS);
          rs.setProperty("message", "brave Neo");
  
          System.out.println(firstNode.getProperty("message"));
          System.out.println(rs.getProperty("message"));
          System.out.println(secondNode.getProperty("message"));
  
          greeting = ((String) firstNode.getProperty("message")) + ((String) rs.getProperty("message"))
                  + ((String) secondNode.getProperty("message"));
  
          tx.success();
  
      }
  }
  
  void removeData() {
      try (Transaction tx = graphdb.beginTx()) {
          firstNode.getSingleRelationship(RelTypes.KNOWS, Direction.OUTGOING).delete();
          firstNode.delete();
          secondNode.delete();
  
          tx.success();
      }
  }
  
  void shutDown() {
      System.out.println();
      System.out.println("Shutting down database......");
      graphdb.shutdown();
  }
  
  private static void registerShutdownHook(final GraphDatabaseService graphdb) {
      Runtime.getRuntime().addShutdownHook(new Thread() {
          @Override
          public void run() {
              graphdb.shutdown();
          }
      });
  }
  </code></pre>
  
  <p>}</p>
  
  <pre><code>&gt;&gt; Traceback (most recent call last):
      File "C:\Projects\Argon\workspace\TestNeo4jProject\src\helloworld\file.py",   line 6, in &lt;module&gt;
      javaClass = jp.JClass('helloworld.Hello')
    File "C:\Python27\lib\site-packages\jpype\_jclass.py", line 54, in JClass
      raise _RUNTIMEEXCEPTION.PYEXC("Class %s not found" % name)
  jpype._jexception.ExceptionPyRaisable: java.lang.Exception: Class helloworld.Hello not found
  </code></pre>
  
  <p>I suppose there could be a Problem with classpath or something like this, but it Looks quite weird for me.. Thank's a lot if somebody can help with the solution! </p>