Eclipse Vert.x 4 beta 1 released!

We are ex­tremely pleased to an­nounce the first 4.0 beta re­lease of Eclipse Vert.x .

Vert.x 4 is the evo­lu­tion of the Vert.x 3.x se­ries that will bring key fea­tures to Vert.x.

Vert.x Web

Fixed CVE-2020-35217.

SQL client metrics

Vert.x 4 sup­ports met­rics for clients which are crit­i­cal for mon­i­tor­ing ap­pli­ca­tion per­for­mance.

While the ca­pa­bil­i­ties are generic and can apply to any client, each client needs a spe­cific in­te­gra­tion. Ob­vi­ously the SQL client was the per­fect can­di­date in mind for this new fea­ture.

Mi­crom­e­ter met­rics will re­port these met­rics as

  • vertx_sql_queue_pend­ing: num­ber of re­quests sched­uled but not yet ex­e­cuted
  • vertx_sql_queue_time: time spent in queue be­fore pro­cess­ing
  • vertx_sql_pro­cess­ing_pend­ing: num­ber of re­quest being processed
  • vertx_sql_pro­cess­ing_time: re­quests la­ten­cies

A better API for JDBC Client

Our JDBC client will not go away in Vert.x 4, we do rec­kn­og­nize that JDBC is im­por­tant be­cause it sup­ports the most im­por­tant num­ber of data­bases in the ecosys­tem.

When we de­signed the SQL client API we strived a lot to come with the sim­plest and most pow­er­ful API for asyn­cho­nous SQL client.

This re­lease brings an im­ple­men­ta­tion of the SQL client API for JDBC.

The 3.x API se­ries will con­tinue to be sup­ported for the life­time of Vert.x 4.

Event loop affinity

Using Vert.x from a non Vert.x thread is a very com­mon use case we have been sup­port­ing since Vert.x 3.

When you use a Vert.x re­source (like a client) from a non Vert.x thread, Vert.x 3 ob­tains a new event-​loop every­time it hap­pens.

In Vert.x 4 we de­cided to pin the first event loop to the non Vert.x thread. The goal is to pre­vent some data races and also makes rea­son­ning about this eas­ier.

Vertx vertx = Vertx.vertx();

for (int i = 0;i < 4;i++) {
  String msg = "Message " + i;
  vertx.runOnContext(v -> {

Run­ning this with Vert.x 3 will print the 4 lines but they are likely to not be re­ordered, this code could also be run­ning in par­al­lel (that is two dif­fer­ent threads run­ning at the same time on a dif­fer­ent CPU core).

Run­ning this with Vert.x 4 will print the 4 lines in the cor­rect order and al­ways with the same thread. This elim­i­nates some po­ten­tial data races and also al­lows to rea­son about what will hap­pen at run­time.

Vert.x Json Schema supports Draft2019-09

The new vertx-​json-schema mod­ule now sup­ports the lat­est Json Schema Draft2019-09 spec. You can fi­nally play with the new $recursiveRef to build ex­ten­si­ble re­cur­sive schemas and with unevaluatedProperties/unevaluatedItems to de­fine strict schemas. Look at the mod­ule doc­u­men­ta­tion to start using it.

Clustering configuration simplified

In Vert.x 3, clus­ter host was set to localhost by de­fault in EventBusOptions. Con­se­quently, a lot of new users were con­fused about why event bus con­sumers and pro­duc­ers were not able to com­mu­ni­cate even if the un­der­ly­ing clus­ter man­ager was con­fig­ured cor­rectly.

Also, when using the CLI tool or the Launcher class, Vert.x tried to find a host among avail­able net­work in­ter­faces if none was pro­vided with the -cluster-host ar­gu­ment. Some­times, the host cho­sen by the clus­ter man­ager and Vert.x were not the same.

Start­ing with Vert.x 4 beta 1, the clus­ter host de­fault has been re­moved and, if users don’t pro­vide any, Vert.x will ask the clus­ter man­ager which one it picked be­fore try­ing to find one it­self. This ap­plies whether Vert.x is em­bed­ded in any Java pro­gram or started with the CLI tool or with the Launcher class.

So far, only vertx-hazelcast and vertx-infinispan clus­ter man­agers can pro­vide Vert.x with a clus­ter host. When other clus­ter man­agers are used, Vert.x will choose one it­self.

Cluster manager upgrades

vertx-hazelcast has been up­graded to Hazel­cast 4.0.2 and vertx-infinispan to In­fin­is­pan 11.0.1.Final.


This is the Beta1 re­lase of Vert.x 4, you can of course ex­pect more betas as we get feed­back from the com­mu­nity and fix is­sues that we failed to catch be­fore.

You can also read the mile­stone an­nounces to know more about the over­ral changes:

The dep­re­ca­tions and break­ing changes can be found on the wiki.

For this re­lease there are no Docker im­ages.

The re­lease ar­ti­facts have been de­ployed to Maven Cen­tral and you can get the dis­tri­b­u­tion on Maven Cen­tral.

You can boot­strap a Vert.x 4.0.0.Beta1 project using

The doc­u­men­ta­tion has been de­ployed on this pre­view web-​site https://vertx-​

That’s it! Happy cod­ing and see you soon on our user or dev chan­nels.

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