Monitoring WildFly using VisualVM

In this updated tutorial we will learn how to connect the latest version of WildFly application server using VisualVM monitoring tool. VisualVM is a free tool to monitor and profile Java application. In the past, VisualVM used to be shipped with Oracle JDK 6~8 as Java VisualVM. It has been discontinued in Oracle JDK 9. … Read more

JBoss Interview questions and answers – Mastertheboss

Are you going for a JBoss / WildFly interview ? here is a comprehensive list of JBoss / WildFly interview questions that will shake up your hiring! General JBoss interview questions Q: Name all possible ways you are aware of to start WildFly application server At least four ways: Option 1) Download and unzip WildFly … Read more

How to create a custom Elytron Realm

In this tutorial we will learn how to create a custom Realm in Elytron, which is the equivalent of the old legacy Login Modules, and we will test it with a sample Web application. The starting point for creating a custom Ream in Elytron is the interface SecurityRealm which contains the contract for a realm backed … Read more

How do you connect a Datasource to a Cluster ?

When connecting WildFly / JBoss EAP to a Database cluster you need to provide an appropriate JDBC Connection String. We’ll examine three popular Database: Oracle, MySQL and PostgreSQL. Oracle Real Application Clusters (RAC) Oracle Real Application Clusters (RAC) is a software component you can add to a high-availability solution that enables users on multiple machines … Read more

Configuring TLS 1.3 on WildFly application Server

This tutorial will teach you how to configure Transport Layer Security (TLS) v.1.3 on WildFly application server. TLS 1.3 offers improved speed compared to TLS 1.2. The earlier version of TLS (1.2) required two round-trips to finish a TLS handshake. On the other hand, TLS 1.3 only needs to complete a single round-trip. This substantially … Read more

How to monitor and invalidate HTTP Sessions in WildFly

This article has been updated to show how to monitor and invalidate HTTP Sessions in WildFly application server / JBoss EAP using management instruments. First of all, in order to gather statistics about HTTP sessions, you need to enable statistics on undertow subsystem You can do it from the CLI as follows: /subsystem=undertow:write-attribute(name=statistics-enabled,value=true) That being … Read more

How to check JVM start up arguments from the Command Line in WildFly

There are several options to collect JVM arguments of WildFly application server from the Command Line. In general terms, if you want to check JVM arguments of a Java process, you can use the ‘jps‘ tool which is available in the ‘bin’ folder of the JDK. Example: jps -lvm 8239 -Djboss.server.base.dir=/home/jboss/wildfly-preview/standalone -D[Standalone] -Xms64m -Xmx512m -XX:MetaspaceSize=96M … Read more

Cannot connect to WildFly CLI? a simple way to solve it

One common issue when you are starting to use WildFly is the following issue. You have tried connecting to the CLI: $ ./jboss-cli.sh -c However the following error is returned: Failed to connect to the controller: The controller is not available at localhost:9990: java.net.ConnectException: WFLYPRT0053: Could not connect to remote+http://localhost:9990. The connection failed: WFLYPRT0053: Could … Read more

How to increase the Transaction Timeout in JBoss / WildFly

Transaction timeout in WildFly / JBoss can be configured in the transactions subsystem or at EJB level. When the transaction is configured in the transactions subsystem it will be the default transaction timeout for all JTA transactions. When configured at EJB level, the timeout will be specific of that EJB. Configuring Transaction timeout in the … Read more

Solving “No managed connections available within configured blocking timeout” error

This article discusses how to solve the error “No managed connections available within configured blocking timeout” which happens when you are not able to collect a Connection object from a WildFly Datasource. Here is an example of this error, which can be found in the application server logs: Caused by: javax.resource.ResourceException: IJ000453: Unable to get … Read more