java - Simple Application using JNDI and DataSource without Server, ServiceUnavailableException, ConnectException

Question

I'm reading about JNDI and DataSource.

• https://www.journaldev.com/2509/java-datasource-jdbc-datasource-example
• https://www.journaldev.com/2513/tomcat-datasource-jndi-example-java
• https://www.baeldung.com/jndi

Does it make sense to use JNDI without a server, e.g. Tomcat, JBoss, WAS?
Is there some simple, standalone application that uses JNDI?

I would like an example using both without a server.

import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.util.Hashtable;
import javax.naming.Context;
import javax.naming.InitialContext;

public class ClassTest {

  public static void main(String[] args) throws RemoteException {
    String title = "java:comp/UserTransaction";
    String host = "localhost";
    int port = 1099;
    System.setSecurityManager(new SecurityManager());
    //System.setSecurityManager(new RMISecurityManager());
    Registry registry = LocateRegistry.getRegistry(host, port);
    Hashtable<String, String> env = new Hashtable() {
      {
        put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");
        //put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.fscontext.RefFSContextFactory");
        put(Context.PROVIDER_URL, "rmi://" + host + ":" + port);
      }
    };
    try {
      Context ctx = new InitialContext(env);
      ctx.bind(title, new ImplRemote("Apple"));
    } catch (Exception ex) {
      ex.printStackTrace();
    }

    try {
      Context ctx = new InitialContext(env);
      String str = ((ImplRemote) ctx.lookup(title)).getValue();
      System.out.println("str:" + str);
    } catch (Exception ex) {
      ex.printStackTrace();
    }

  }

  static class ImplRemote implements Remote {

    private String value;

    public ImplRemote(String value) {
      this.value = value;
    }

    public String getValue() {
      return value;
    }

    public void setValue(String value) {
      this.value = value;
    }

  }

}

Executing

$ java -Djava.security.policy=<(echo 'grant {permission java.security.AllPermission;};') ClassTest
javax.naming.ServiceUnavailableException [Root exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: 
    java.net.ConnectException: Connection refused (Connection refused)]
    at com.sun.jndi.rmi.registry.RegistryContext.bind(RegistryContext.java:161)
    at com.sun.jndi.rmi.registry.RegistryContext.bind(RegistryContext.java:166)
    at javax.naming.InitialContext.bind(InitialContext.java:425)
    at ClassTest.main(ClassTest.java:71)
Caused by: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: 
    java.net.ConnectException: Connection refused (Connection refused)
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:619)
    at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216)
    at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
    at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:338)
    at sun.rmi.registry.RegistryImpl_Stub.bind(RegistryImpl_Stub.java:60)
    at com.sun.jndi.rmi.registry.RegistryContext.bind(RegistryContext.java:155)
    ... 3 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at java.net.Socket.connect(Socket.java:538)
    at java.net.Socket.<init>(Socket.java:434)
    at java.net.Socket.<init>(Socket.java:211)
    at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40)
    at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:148)
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:613)
    ... 8 more
javax.naming.ServiceUnavailableException [Root exception is java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: 
    java.net.ConnectException: Connection refused (Connection refused)]
    at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:136)
    at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:142)
    at javax.naming.InitialContext.lookup(InitialContext.java:417)
    at ClassTest.main(ClassTest.java:78)
Caused by: java.rmi.ConnectException: Connection refused to host: localhost; nested exception is: 
    java.net.ConnectException: Connection refused (Connection refused)
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:619)
    at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216)
    at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
    at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:338)
    at sun.rmi.registry.RegistryImpl_Stub.lookup(RegistryImpl_Stub.java:112)
    at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:132)
    ... 3 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at java.net.Socket.connect(Socket.java:538)
    at java.net.Socket.<init>(Socket.java:434)
    at java.net.Socket.<init>(Socket.java:211)
    at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40)
    at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:148)
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:613)
    ... 8 more
$ 

Thanks.

Answer 1

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