Porting Weblogic T3 RMI client to Java 17

Question

I am moving my old SpringBoot 2 / Java 8 application to the newer SpringBoot 3 / Java 17.

My issue is related to the Weblogic T3 client. Until now I used the wlthint3client artifact coming from a Weblogic 12.2.1.3 installation (compiled by Java 8) which runs with no issues.

Using the same artifact inside the new architecture, based on SpringBoot 3 / Java 17 the new InitialContext(environment) instruction stucks forever!!!

Could anybody tell me if there exist a newer release of the Weblogic Client, or a workaround for that issue?

Here is a fragment of the code which uses the client:

public static MyRemoteEJB lookup(
    String clusterAddress,
    String userName,
    String password
)
    throws NamingException
{
    Properties environment = new Properties();

    environment.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
    environment.put(Context.PROVIDER_URL,            clusterAddress);

    if (null != userName) {
        environment.put(Context.SECURITY_PRINCIPAL, userName);
    }

    if (null != password) {
        environment.put(Context.SECURITY_CREDENTIALS, password);
    }

    environment.put("weblogic.jndi.allowExternalAppLookup", "true");
    environment.put("weblogic.jndi.relaxVersionLookup",     "true");

    InitialContext context      = new InitialContext(environment);
    String         resourceName = String.format(
        "remote-app#%s",
        MyRemoteEJB.class.getName()
    );

    return (MyRemoteEJB)context.lookup(resourceName);
}

Thank you so much!

Preventive

If you really using Spring Boot 3... than you have to use JDK17 because SB 3 requires JDK 17+ (docs.spring.io/spring-boot/docs/3.0.9/reference/htmlsingle/…) ... – Presidio

Sorry it was a typo. I am using java 17. – Preventive

It could be a network issue or a java issue as WebLogic 12.2.1.3 does not support Java 17. Add following JVM args to set timeouts to your T3 connection : -Dweblogic.jndi.connectTimeout=300000 -Dweblogic.jndi.responseReadTimeout=300000 – Bailiff

I debugged the Weblogic T3 Thin Client and I found the exception raised only for Java 17, and I discovered that the bug is known, but I have no access to the Oracle Portal at support.oracle.com/knowledge/Middleware/2928858_1.html . – Preventive

Answer 1

With a lot of effort, I finally solved the issue!

I am going to describe which the solution is, and how I achieved it.

The first step was to ask to the Oracle support, provided by my company, the Jakarta version of the Weblogic T3 Thin Client shipped with Weblogic 14.1.1.0.

I decompiled and debugged it by the IntelliJ built-in java decompiler to get enough information to active and redirect the T3 client debug logs to my console (look at the below source code).

Here the relevant source code:

logging.properties

handlers=java.util.logging.ConsoleHandler
.level=FINE

java.util.logging.ConsoleHandler.level=FINE
java.util.logging.ConsoleHandler.formatter=java.util.logging.SimpleFormatter

Main.java

package org.example;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import java.util.Properties;
import java.util.logging.Logger;

public class Main {
    private static final Logger logger = Logger.getLogger(Main.class.getName());

    private static void loggerSetup() {
        String pwd = System.getenv("PWD");

        System.setProperty(
            "java.util.logging.config.file",
            (pwd + "/src/main/resources/logging.properties")
        );

        System.setProperty("com.bea.core.debug.DebugLegacy.stdout", "true");
        System.setProperty("weblogic.diagnostics.debug.DebugLogger.DISABLED", "false");

        System.setProperty("weblogic.debug.DebugAbbrevs", "true");
        System.setProperty("weblogic.debug.DebugAllowList", "true");
        //System.setProperty("weblogic.debug.DebugClassLoadingContextualTrace", "true");
        //System.setProperty("weblogic.debug.DebugClassLoadingVerbose", "true");
        System.setProperty("weblogic.debug.DebugCluster", "true");
        System.setProperty("weblogic.debug.DebugClusterVerbose", "true");
        System.setProperty("weblogic.debug.DebugConnection", "true");
        System.setProperty("weblogic.debug.DebugDGCEnrollment", "true");
        System.setProperty("weblogic.debug.DebugFailOver", "true");
        System.setProperty("weblogic.debug.DebugGenericMethodDescriptor", "true");
        System.setProperty("weblogic.debug.DebugJNDI", "true");
        System.setProperty("weblogic.debug.DebugJVMID", "true");
        System.setProperty("weblogic.debug.DebugLegacy", "true");
        System.setProperty("weblogic.debug.DebugLoadBalancing", "true");
        System.setProperty("weblogic.debug.DebugMessaging", "true");
        System.setProperty("weblogic.debug.DebugRMIRequestPerf", "true");
        System.setProperty("weblogic.debug.DebugRouting", "true");
        System.setProperty("weblogic.debug.DebugStubGeneration", "true");
        System.setProperty("weblogic.debug.ServerHelp", "true");
    }

    private static Object lookup(
        String clusterAddress,
        String userName,
        String password
    )
        throws NamingException
    {
        Properties environment = new Properties();

        environment.put(Context.INITIAL_CONTEXT_FACTORY, "weblogic.jndi.WLInitialContextFactory");
        environment.put(Context.PROVIDER_URL,            clusterAddress);

        if (null != userName) {
            environment.put(Context.SECURITY_PRINCIPAL, userName);
        }

        if (null != password) {
            environment.put(Context.SECURITY_CREDENTIALS, password);
        }

        environment.put("weblogic.jndi.allowExternalAppLookup", "true");
        environment.put("weblogic.jndi.relaxVersionLookup",     "true");

        InitialContext context      = new InitialContext(environment);
        String         resourceName = String.format(
            "remote-app#%s",
            MyRemoteEJB.class.getName()
        );


        return context.lookup(resourceName);
    }

    public static void main(String[] args) {
        loggerSetup();

        logger.info("Connecting...");

        try {

            Object myRemoterEJB = lookup("t3://127.0.0.1:7002", null, null);

            if (null != sogeiAdapterEJB) {
                logger.info("Remove EJB got!");
            }

        } catch(NamingException e) {
            String message = e.getMessage();

            if (message.contains("MyRemoteEJB")) {
                logger.info("Remote EJB got, but not marshaled.");
            } else {
                logger.severe(message);
            }
        }
    }

}

Running it I got several exceptions, but only one really related to my problem:

java.lang.reflect.InaccessibleObjectException: Unable to make private static java.lang.ClassLoader java.io.ObjectInputStream.latestUserDefinedLoader() accessible: module java.base does not "opens java.io" to unnamed module @50675690

The above one was the root cause of:

Try to create JVM connection 1 time, encounter : java.io.IOException: Timed out while attempting to establish connection to :t3://127.0.0.1:7002

The solution was provided by this post, so I added the JVM arguments:

--add-opens java.base/java.lang=ALL-UNNAMED --add-opens java.base/java.util=ALL-UNNAMED --add-opens java.base/java.io=ALL-UNNAMED

All the connections issues are gone!!!

Preventive

Thanks for your response. Did you manage to integrate that with your maven project? How did you do that? – Bramble

Those paramereters must be put on the JVM command line, not in maven. – Preventive

Thanks. After migrating my project to jdk17 and passins those flags to the jvm I am getting the same connection error (with jdk8 works fine the connection) – Bramble

Very strange, it works for me and many others. Please, post your command line here... – Preventive

Answer 2

Thanks, I was getting the same error. For me adding the following flag helped:

--add-opens=java.base/java.io=ALL-UNNAMED

It's nice to know how to get the logging up and running.

Ticker